Link4 Invoice Express

Advanced Ordering & Order Balance

User Guide

🔹 Introduction

This guide explains how Link4 Invoice Express supports Advanced Ordering and SG BIS Order Balance for B2G transactions. It documents the full set of scenarios tested, describes how orders and related messages flow through the system, and outlines the step-by-step actions needed to receive, respond to, flip, and invoice government purchase orders.

The User guide covers:

● Requirements Vendors would have to comply To submit e-invoices to Singapore government agencies via InvoiceNow
● Receiving Purchase Orders, Order Changes, Order Cancellations, and Order Balance documents.
● All required B2G and B2B fields to Flip received purchase Orders to Invoices
● Different types of received advanced orders and user interface steps
● Sending invoices to AGD and receiving invoice responses.
● Generating direct B2G invoices without a preceding order.
● Required user interface steps inside Link4 Invoice Express.

1️⃣ Requirements

To submit e-invoices to Singapore government agencies via InvoiceNow, vendors would have to comply with the following requirements:

1) Have a CorpPass account at CorpPass portal (Corppass.gov.sg)

• To find out how to register for a CorpPass account and set up the Vendors@Gov e-service at the CorpPass portal, please refer to this guide.

2) Have an “Approved” vendor record at Vendors@Gov (vendors.gov.sg)

1. Before submitting e-invoices to Singapore government agencies via the network, vendors would first need to create a vendor record at Vendors@Gov. Vendors can log into Vendors@Gov using CorpPass.

2. The vendor record has to be of “Approved” status before e-invoice submission.

3. Payment will be made based on the bank details provided in the vendor record

4. To find out how to login at Vendors@Gov, please refer to this guide.

5. To find out how to create a vendor record, please refer to this guide.

3) Ensure that e-invoices are submitted based on the e-invoice requirements of Singapore government agencies

Note:
If you have submitted an e-invoice via InvoiceNow, there is no need to submit the e-invoice again via Vendors@Gov.

If there is non-compliance with the above requirements, the e-invoice will be rejected and you will be notified via email based on the email address in your vendor record or provided in your InvoiceNow invoice.

• For clarity on this requirements, Please refer to the Venders Gov user guide through this link

2️⃣ Overview of Advanced Ordering

Advanced Ordering extends the InvoiceNow ecosystem to support the full ordering lifecycle:

● Order (PO) – gov agency issues an order.
● Order Change (Variation) – gov agency varies quantities, prices, dates, or other fields.
● Order Cancellation – gov agency cancels a previously issued order.
● Order Response – supplier accepts or declines an order.
● Order Balance – updated view of remaining quantities, values, and line status.
● Invoice response - Invoice response received from the buyer.

Link4 Invoice Express fully supports each document type and can manage the lifecycle from receipt through invoicing.

3️⃣ Required fields for Full invoice flipping (B2B & B2G)

When flipping an order (or variation) to an invoice, the following fields must be added mandatory from the received order or from the supplier master profile.

3.1 General Flipping (B2B & B2G)

● Purchase Order ID
● Currency
● Unit Price (per line)
● Order Line Reference

3.2 Additional Flipping Required for B2G (typically not expected for B2B)

● Business Unit (Sub-BU)
● Attention To / Contact Person
● Vendor ID
● Supplier Email Address
● Payment Terms
● Invoice Line Description

3.3 Reference Only (no flipping required)

● Invoice Line Amount (excluding GST)
● Invoice Line Quantity

Link4 performs all required population automatically once the order is selected for flipping.

4️⃣ User flow of Receiving of Advanced orders

This section lists all the scenarios, aligned with IMDA’s Advanced Ordering and Order Balance test matrix.

4.1 Full Order Flipping

4.1.1 – Receive Order (Govt)

Link4 User receives an Order.

UI will display following required fields:
Order ID, Order Notes, payment terms, customer details, Customer references, Document delivery destination, buyer contact name and email, order line notes, and delivery dates.

Step 1 - Go to the link4 dashboard. In the menu, click on Advanced Orders, then expand the + icon and select Advanced Orders List.
Step 2 - In the Advanced Orders window, select the tab labeled Received PO. Filter by 'Order', then click Apply. You will see all the received purchase orders.

4.1.2 – Receive Order Balance (Govt)

Link4 user can receive an Order Balance document as well to the original order.

Link4 UI display same required fields as mentioned:
Order ID, Order Notes, payment terms, customer details, Customer references, Document delivery destination, buyer contact name and email, order line notes, and delivery dates.

Step 1 - Go to the link4 dashboard. In the menu, click on Advanced Orders, then expand the + icon and select Advanced Orders List.
Step 2 - In the Advanced Orders window, select the tab labeled Received PO. Filter by 'Order balance', then click Apply. You will see all the received purchase order balance documents.

4.1.3 – Flip Order to Invoice

Link4 User can then flips the received purchase order to invoice and link4 will auto-populates all required fields (buyer reference, contact person, vendor ID, supplier email, payment terms, order ID, invoice note, PO line reference, invoice line description, supplier legal name).

Step 1 - Go to the link4 dashboard.
Step 2 - Select Received PO and filter by 'Order' or 'order balance', then click Apply.
Step 3 - Open the desired PO document type.
Step 4 - Scroll to the bottom of the purchase order document and click the 'Order to Invoice' button.

4.1.4 – Send Invoice to Government

Invoice status changes to “Sent Successfully”. User can check this in the sent invoices log details page.

Step 1: Go to Invoices in the left menu and open the Invoice List.

4.1.5 – Receive Invoice Response (AB/IP/RE Etc)

Link4 users will receive responses from the buyer.

To view the received response, open the same sent invoice document and scroll down to the Invoice Response log. All received responses will be listed there.

4.2 Order Change / Variation Flow

4.2.1 – Receive Order (Govt)

Users will be able to view received purchase orders in the "Received PO -> Order" tab.

4.2.2 – Receive Order Change

Users will be able to view the received purchase order change document in the "Received PO -> Order change" tab.

4.2.3 – Flip Order Change to Invoice

Step 1 - In the order change document, scroll down to Document History and click 'View Document' next to original Order Transaction.
Step 2 - From the original order, click 'Order to Invoice'.
Step 3 - On Edit Invoice page, review and click Send as e-Invoice.

4.2.4 – Send Invoice to AGD

Navigation:

Step 1 - Go to Invoices in the left menu and open the Invoice List. Find the invoice you created and click the invoice number

4.2.5 – Receive Invoice Response (AB/IP/RE)

Open the sent invoice and scroll to Invoice Response log to view status.

4.3 Order Cancellation

4.3.1 – Receive Order (Govt)

Users will be able to view received purchase orders in the "Received PO -> Order" tab.

4.3.2 – Receive Order Cancellation

User will receive order cancellation and shows the cancellation status in the order.
System updates order status to Cancelled.

4.4 Order Response

4.4.1 – Receive Order

Users will be able to view received purchase orders in the "Received PO -> Order" tab.

4.4.2 – Send Order Response (AB)

Respond with Accepted with Backorder.

Step 1 - Scroll to bottom of original order and click 'send order response'.

4.5 Direct Invoicing to Government

4.5.1 – Create Direct Invoice Using Ministries / SB List

User can select Ministry / Stat Board and its Sub-BU from the maintained list.

Step 1: Add Government Customer

Option 1 – Manual Add (Available Now)

1. Go to My Network in Link4 Invoice Express.

2. Click Add Customer.

3. Enter:
   ▪ Email
   ▪ UEN
   ▪ Peppol ID

4. Save the customer.
   

Option 2 – Bulk Upload (Coming Soon)

1. Download CSV template.

2. Fill in UEN, Peppol ID, Buyer email, Buyer reference number.

3. Upload CSV.

Option 3 – Auto-Maintained Government List (Coming Soon)

Select from dropdown list and the gov entity will auto populate the relevant buyer reference number as well. 

4.5.2 – Send Direct Invoice to AGD

Step 1: Create Direct Invoice

1. Go to Invoices.

2. Click + button.

3. Select government customer.

4. Enter invoice line details.

5. Verify below fields data:

            ● Buyer Reference (Sub-BU)
            ● Customer Contact Person
            ● Vendor ID
            ● Supplier Email Address
            ● Payment Terms Notes
            ● Invoice Note
            ● Invoice Line Description
            ● Supplier Legal Company Name

4.5.3 – Receive Invoice Response (AB/IP/RE)

Open submitted invoice → Scroll to “Invoice Response” section to check status.

AGD & IMDA Requirements for Direct Invoicing to Government

When issuing a direct e-invoice to a Singapore Government agency through InvoiceNow, suppliers must comply with the technical and data requirements defined by IMDA and the Accountant-General’s Department (AGD).

1️⃣ Peppol Endpoint for Government Invoices

● Default AGD Endpoint ID: 0195:SGUENT08GA0028A
● Link4 will use the appropriate endpoint based on the customer record created by the vendor.

2️⃣ AGD Mandatory Data Fields (B2G-Only Requirements)

For more info about the fields refer to the link:
https://www.vendors.gov.sg/doc/Guide-E-invoice_Submission_via_InvoiceNow_Technical.pdf?ver=1.4

2.1 Header-Level Mandatory Fields

2.2 Line-Level Mandatory Fields

2.3 Fields Required Only When Referencing a Purchase Order / Instruction

Billing against a PO or Invoicing Instruction

3️⃣ AGD Validation Rules Applied After Submission

Invoice will be rejected if:

● Mandatory B2G field missing
● Vendor ID mismatch
● Invoice date invalid
● PO/Sub-BU reference incorrect
● GST non-compliance
● Unsupported charges included

Rejected invoice response includes:

● Status: RE
● Reason code
● Explanation
● Invoice Number
● Invoice Date

Users must correct and resend.

4️⃣ Government Invoice Response Status Codes

5️⃣ How Link4 Ensures Compliance

● Injects Buyer Reference (Sub-BU)
● Validates Peppol ID and UEN
● Populates Vendor ID
● Enforces mandatory fields
● Sends to correct AGD endpoint
● Displays Invoice Response statuses

6️⃣ Compliance

Link4 Invoice Express conforms to:

● Peppol Advanced Ordering specifications.
● SG BIS Order Balance requirements.
● IMDA IRSP certification expectations.
● Required flipping rules for B2G transactions.

This guide is suitable for submission to IMDA as evidence of functionality and documentation readiness.