SA100 submission to HMRC
SA100 submission to HMRC
Once your client has approved their return, you can submit it to HMRC. Submission generates an IR Mark (receipt ID) as proof that HMRC has received the return.
Prerequisites
Before you can submit:
Client approval obtained (through any means: software approval, post, email, verbal, etc.)
HMRC Online Services credentials entered in your Agent Profile
All mandatory fields completed on the tax return (no validation errors)
Online Services credentials are for SA100 submissions. Agent Services credentials are for MTD submissions.
How to Submit
Go to Tax Submission
Select tax year
SA100 Submission tab
At the bottom of the page, you'll see three buttons: Submit to HMRC, Request client approval, and Mark as ready for review
Tick the checkbox: I confirm that my client has received a copy of the information contained in this return and approved the information as being correct and complete to the best of their knowledge and belief
Select Submit to HMRC
A modal appears asking for your HMRC Government Gateway password
Enter your password and select Next
The system submits the return to HMRC
After Submission
You'll see:
- Receipt ID (IR Mark) — Proof the return was received by HMRC
- Submission date
- Tax calculation breakdown
Your client receives:
- An email confirming submission (if they're connected to the software)
- Login link to access and download the submitted return
Your dashboard:
- Client tile moves to the Submitted column on the kanban board
Download the tax return PDF
Download the submission report (includes IR Mark, submission date, and all submitted information)