Vibrate with ringing sound together

For notifications:

Also you can go to this settings page from: your device’s settings -> (App &)Notification -> Reminder FLEX -> Reminder alerts -> Turn on “Vibrate”.

Note: If “Reminder alerts” is not in the list, you just back to app, then set new reminder without setting time. then immediately the alert will go off. Then back to this settings again. “Reminder alerts” now shows up.

For Alarms: