Hi Rainbow485,
To file your return online, please enrol here:
Sign in using Government Gateway
Please select 'Government Gateway’ (log in with your User ID and Password if you are not already done so).
Select 'enrol for service' at the side of Self Assessment on the 'Services you can add' page
Then enter your UTR and postcode instead of your National Insurance number as there may be an error in the NINO online
If you have chosen to have your activation code in the post, you will receive it within 10 working days
You must log in with the same User ID and Password when you get it, otherwise you will not be able to activate your account
Thank you.