My Reminders are normally automatically set for when your project has activity dependencies.
If you want, however, to manually set or change the My Reminder date of an activity:
Open a project and select an activity.
Select the My Reminder column next to an activity and choose a date when you want the system to remind you to take action.
When you set a dynamic reminder for an activity, the activity ends up in your My Reminders Hub.
Note: You can manually set/change the My reminder date of an activity if you are responsible for the project’s execution.