All reminders are system generated, you are able to choose when these reminders are generated by setting your triggers.
To set reminder trigger:
Task Manager -> Reminders Tab -> Reminder trigger settings ->Input criteria -> Save Trigger Settings
Customer level reminders trigger settings step by step manual:
1) Go into the task manager select the reminders tab – select reminders trigger settings
2) Input the preferred number of days without customer interaction who has at least one invoice with X number of overdue days
3) Save trigger settings
Invoice level reminders trigger settings step by step manual:
1) Go into the task manager select the reminders tab – select reminders trigger settings
2) Input the preferred number of days for a specific invoice reminder to be triggered. You can several invoice triggers.
3) Always remember to save trigger settings.