For the overdue invoices by default, functionality is available in Accounting ‣ Sales ‣ Follow-up Reports. There, you can easily send a reminder by email or print it as a letter.

Then, you can click on the Done button to view the next follow-up that needs your attention.

Otherwise, if now is not the time for a reminder, click on Remind me later. You will get the next report according to the Next Reminder Date set on the statement.

To avoid sending too many reminders in a short period of time, change the number of days calculated between each report by going to Accounting ‣ Configuration ‣ Settings ‣ Payment Follow-up.

To get your follow-up process easier, you can send reminder emails in batch from your follow-up reports page. 

Select all the reports you would like to process, click on Action and then on Process Follow-ups. 

A pdf document containing all of the follow-up letters for you to print will also be automatically generated.

To plan a follow-up process, go to Accounting ‣ Configuration ‣ Settings and activate the Follow-up Levels feature under the Customer Payments section.

Then, click on the new Follow-up Levels button that has appeared on your settings page.

If you would like to get a reminder before the actual due date, set a negative number of due days.