You can use the software suppliers in this list to submit valid tax returns, supplementary pages and attachments for the products in this guide.
Some commercial software includes a feature that allows you to get details from HMRC to help you:
complete your client’s Self Assessment tax return if you’re an agent
complete your Self Assessment tax return if you’re an individual
Check with your software supplier to find out if their product includes the feature.
Get technical support if you’re a Self Assessment software developer.