I have been doing federal taxes online for 10 or more years, using irs free file fillable forms:

https://www.irs.gov/filing/free-file-do-your-federal-taxes-f...

It does some calculations itself, and some you have to do yourself, but it is very easy to use and file online, and get a pdf return to save for yourself.

Any half decent state also has had free online tax return filing for some time now.