Hello ewangoil,
You will need to make sure you have reviewed all transactions up until the end of your self employment. If you are confident you have done this, you can then download your tax summary - double check that this is showing the correct figures for your income/expenses and that you have categorised transactions correctly. You can then use this to submit your self assessment on HMRC's site, once you are ready.
We would advise to speak to an accountant if you are able to who will be able to double check this all for you.
Thanks,
Talia