Federal Filing Requirements when Closing a C-Corp

I have had a C-Corp since 1982.  It was a one-person software company.  I decided to close the business on 12/31/2021.  I filed "Articles of Dissolution" with my state.

 

What do I have to file with the Federal government to correctly close the business? I think that I have to file a Form-966 and the final Form-1120 with the "Final Return Box" checked, but is there some other form that I have to file, or is there some other action that I must take.

Thank you.