I just e-filed, but I made a mistake and did not include my CRP, certificate of rent paid. Can I amend the m1pr form at this point?

Good news!  It appears that you are using TurboTax.  Form M1PR was not included with your e-filed return - it can only be filed via US mail. You can go back to your return and make the necessary corrections to Form M1PR and print the return and mail it in to file.