You have passed your 12th in 2020 but you are appearing for Improvement exams only to improve your percentage. So the year of "passing" will remain 2020. So while you are filling the JEE Mains application form, your Year of passing will be 2020. You will need the following documents to upload for JEE Mains:

1. Your recent photograph either in colour or black & white with 80% face but without mask and the face should ve visible including ears against white background.
2. Your Scanned photograph and signature should be in JPG or JPEG format. No Pdf format will be accepted.
3. Size of your scanned photograph should be between 10 kb to 200 kb.
4. Size of your scanned signature should be between 4 kb to 30 kb
5. Size of your scanned copy of category certificate only if applicable should be between 50 kb to 300 kb
6. Size of the scanned copy of PwD certificate if applicable  should be between 50 kb to 300 kb