you need to file a final partnership return for 2020 reporting all its activity thru the date it ceased to be a partnership. you may want to consult a tax pro because there can be some tricky tax issues when a partnership terminates especially if partners have negative capital a/c's, you are using the cash basis and there existed inventory or trade receivables, debt, property, etc. from then on the activity gets reported on your schedule C. do not use the partnership EIN on your schedule C or for any other purpose. if you prefer you can apply for an EIN as a sole proprietor, it's not required but then you may have to furnish your SSN to third parties so they can file required tax reporting forms. since the partnership seems to have terminated in October 2020 a final return was due 2/15/2021. so now it seems to be late with a potential penalty of $200/month/partner - another reason to using a pro.
