I do not have a form 6251.I didn't have one last year, did I?

Line 4 of Form 6251 is your "Alternative Minimum Taxable Income" - there is no way we can tell if you had that form in your 2019 tax return.

See Form 6251 Alternative Minimum Tax—Individuals

can you post a 2019 form 6251 because i did not have one in my 2019 file

Here is the 2019 form 6251, and here are the instructions.