I am amending my return by changing filing status from head of household to single. Do I need to print it out and mail it? If so, where do I mail it?

If you e-filed the original 2020 federal tax return then you can e-file the 2020 amended tax return, Form 1040-X.  Otherwise you will have to print and mail the amended tax return.  The Filing Instructions will have the address on where to mail when you print the amended tax return for mailing.