Enroll Members in Auto-Renewals from the Back Office
When you add membership transactions in the back office — from the Add a membership screen or a membership dues batch — you can enroll new and existing members in auto-renewals

From the Add a membership or Enter membership dues screen, under What are they paying for?, select Renew this membership automatically when it expires. (Credit card required).
Under How are they paying? enter the credit card number to pay for this membership and for the renewal.

From a member's record, under Recent membership transactions, select their most recent membership transaction. and select Edit.
On the Edit a membership transaction screen, select Renew automatically by credit card and enter the credit card number.
You can verify whether a member is enrolled in automatic renewals on their membership record.