1. Go to the Aging Report page.
2. Hover over the "Select all on page" checkbox, and you will see another checkbox to select all companies
3. Click the "Send Reminder" button
4. Create and send an email
Note, you will receive a warning of some of your customers don't have email contacts and the message will not be sent.
Also, keep in mind that if you have a lot of customers it will take some time to send all the reminders. It happens as in order to avoid sending too many messages (which is blocked by many email servers), YayPay adds a random pause of a few seconds between sending individual messages.