It is the merchants responsibility to ensure that they have the appropriate permission to deduct funds from tenants. As such there is a default Pre-Authorized form already created but this should be reviewed and/or edited to ensure it meets your requirements.
It is best practice to let tenants set up their own auto pay, however, you can do it as well from the back end. Please see the steps below.
Please note: The below instructions only work if a payment method is already in the system. HERE is the article on creating a payment method
Step 1: Click on the tenant in question.
Step 2: Click on Edit.
Step 3: Go to Auto Pay tab and click on the "+" sign to add a new Auto Pay.
Step 4: Click on the drop-down in Payment Method and select the method.
Step 5: Configure the First Billing Cycle and Lease Charge amounts if necessary. Once done, click save