Go to "Invoicing" Tab, then "Bulk Invoicing"
Select the dates of the most recent invoice, then click "Show Report"
Click on the little credit card picture to the right of the "Payment Type" column
This will sort the list into clients with a Green S, and clients without.
Green S represents clients with Stripe information on file. Any clients missing Green S do not currently have payment method on file.
To email clients without payment method on file, click the check box to the right of any clients without a Green S on top. In top left corner click "Email".
Select email template, add subject line, edit if necessary and send!