Push notification vs local notification in my project

Hi everyone,

The case for my ionic project is: Assume my app is a forum app, user A creates a new post in the app, then the app will send the notification to other users that the new post is just created by user A.

So my question is:
If I want to implement the Notification functions in my ionic app, I should implement the Push notification while not local notification, am I right? As I am new in Notification issues.

Also, are there any references to me for this situation? As most push notification tutorials on Google are all sending notification from server to user’s app which are not suitable in my situation.

Thank you.