Missed 5 October deadline

Hi. My son was not aware of the deadline of 5 October and has registered late. It now says he is not due to pay tax in 2023/24 but he became self employed about half way through the year and probably will have to pay some tax. How can he submit a return because, every time he tries to access the self assessment area, it says he doesn't need to pay tax?

Hi,
It is possible that, while your son has registered for Self Assessment, he may not have registered to file a return for the 2023 to 2024 tax year. He may also need to register to file his tax returns online through his personal tax account. To allow us to confirm what your son needs to do, he need to contact our Self Assessment team.
Self Assessment: general enquiries
Thank you.