I am graduate 2020 DEC and my F-1 status end in March 10th, I should use 1099 report the year 2020 and 1040 to report for the following year right ?

Then I need to file tax, how much percentage is the tax and can my gain offset with some of my lost ? is the form 1042-s I should use ?

Thank you so much for your fast reply. Just want to clearly by cash out you mean take out the money from my trading account or just simply sold a stock (the fou...