Hi
If you are referring to the tax return SA800, then you can submit online, if you can verify your identity and obtain a government gateway user ID and password.
You would need to buy a commercial tax return to complese and submit with your ID and password, the only other alternative is a paper tax return.
There are several ways to pay tax, perhaps one of the options at (
Select the tax you want to pay) will be suitable.
Thank you.