Instructions apply to iOS 16 and later.
Even with your system, though, you may still overlook a few.
The email reminder feature can help you reply to every important email.

If you chooseRemind Me Later, use the calendar to select a day.
Move theTimeslider to on/green and then select a time.
TapDoneto set the reminder for the day and time you’ve selected.

In your inbox, messages with reminders set on them have a small clock icon at the far right.
you might also remove a reminder once it’s been set.
To do that, follow the first 3 steps above, and then tapRemove Reminder.
If you backed up your phone, sign in to iCloud.
From theApps & Datascreen, tapRestore from iCloud Backuptorestore your iPhone.
To get reminders for iPhone Calendar events, go toSettings>Notifications>Calendarand turn onAllow Notifications.
TapCustomize Notificationsfor more options.
Alternatively,use the Reminders app.