By toggling on Authorize Only, the amount charged will be held until you complete the next step of actually capturing them. You'll be able to capture and charge for the entire amount, or a percentage of the entire amount. The funds will be held for a period of time until you choose Process and then if the funds are not processed the hold will be removed and no amount will be charged. The amount of time before it expires depends on each Payment Processor however the average is usually 7 days.
This may be helpful if you'd like to approve a form submitter's application before you capture their funds. Another great example is Public Records Requests where an individual may authorize up to a certain amount but not over that. If their request ends up being less than they've authorized then you can charge a percentage of the pre-authorized amount instead.
When the user goes to pay, the button will say Pre-Authorize Payment to notify them of the hold:
To capture authorized funds, you will go to a submission in the form's Submissions Manager. From there it will denote that a payment has been Pre-Authorized and will show $0.00 under Total Collected until Authorized:
Then you can click on the submission to open up the Submission panel on the right hand side. There you will see a button that says Process Payment which will open up to allow you to process all, or a portion, of the funds:
After clicking on Process Payment you it will then allow you to choose to process a specific dollar amount, or a percentage, of the pre-authorized amount:
After you've chosen the amount, you can click on Process Payment and it will charge the amount you've chosen.
NOTE: Payments will be authorized for a period of time, not indefinitely. This period of time depends on the payment processor and the average is typically 7 days. After that period of time has elapsed the hold will be removed and no amount will be charged.