Custom Function or Workflow Process to Charge Card on File

Custom Function or Workflow Process to Charge Card on File

I would like to send a recurring invoice on the 15th of the month and then automatically charge the customer's card on file on the last day of the month. I see in Workflow where recurring invoices can automatically be created. sent and charge the card on file. I do not want the card on file to be charged immediately however. I do not see where a delay in charging the card on file can be set so I was thinking maybe a custom function could be created to handle this. After looking through the available documentation, I didn't see anything that interacts with charging a card on file.

Does anyone else do something like this? Any pointers will be greatly appreciated!

Thank you,
Matt