Depends on what you mean by "auto-payment."
Auto-draft: a service provider drafts an account at another bank. Example of this service is ClearNow, sponsored by this site. Click on "Services" above for details. Tenant must fill out a form, authorizing the service. There is typically a per transaction charge that may go down after so many transactions per month.
Automatic paycheck payment: Tenant requests their HR dept to send $X out of each paycheck to you, similar to other auto-debits like health insurance, 401K contributions, etc. Again, tenant must do this: you cannot just start tapping their paycheck without permission. This is typically a free service, but only offered my medium or large employers. Pa Kettle's 5 man fix-it garage won't have this, usually.
Bank bill pay. You give tenant info and they set up a payment, usually using their bank's online bill pay service. Some banks can find your bank using a data base and turn them into E-payments; others just mail a paper check debited against the tenant's account. Also usually free or very inexpensive, but tenant can shut it off at any time without warning.
Automated debit/credit card charge: You set up an online service with a credit/debit card processor (example "Square"), the tenant gives you the card information which you enter into the online software, and then each month the company charges the card. Usually involved a percentage transaction fee + a minimum charge. Square's fee for regularly scheduled transactions is something like 2.5% + 40 cents per transaction. One-off transactions cost more (3.9%, I think).
There may be other methods, but these are the ones I am most familiar with.
--173.19.xx.xxx