Hi Rachel,
You can only submit a commercial tax return, if you can verify your identity, to obtain a government gateway user ID and password.
Once you have that, you can buy a commercial tax return that include the residence section and submit the tax return in its entirity, online, before 31 January 2024.
A list of commercial suppliers can be found at:
Self Assessment commercial software suppliers
If you cannot verify your identity, you cannot use this process and instead, you will need to dowload a paper tax return and supplementary pages.
Fill them out and post them to HMRC.
The due date for paper tax returns was 31 October, so a late filing penalty would apply.
Self Assessment tax return forms
Penalties can be appeal on form SA370:
Self Assessment: appeal against penalties for late filing and late payment
Once hmrc have your tax return.
Thank you.