Getting user data

I am using the ionic push plugin and am having a hard time understanding what it is used for. Originally I was trying to implement it into my app for live chatting, like if one user sends a message to another it would update automatically can I use it for this? Also since there are users being created and saved on our ionic accounts can we use that user info inside of our app like can we get a get method to get the username and birth date of one of the users. The site when your logged in seems like it stores the user info in such a way that it can be used as a database but can I actually get this information from my app and use the data to create a profile view of a user?