Notifications- every day, how to do it?

How to do that every day, in 14:00, the user will recieve notification?

The app must be work in the background to track the time every time, however App Inventor apps can’t run in the background.

You can use OneSignal component if you want to send a manual notification to your app’s users. But as far I know, there is no method to send a notification every day in 14:00 automatically.

Alternatively, Taifun’s method can help you with background services a bit, you can find it here:
http://puravidaapps.com/alarmmanager.php

@yusufcihan has elaborated, I just want to add to him:
you can save a notification as a draft and send it every day (bothering)
or you can visit this link, it helps you to send notifications based on Segments but it does not send every day, but still have some great features:

also, I found something which sends weekly notifications, I don’t know if it can be switched to daily, you can have a look: