Suppose you want to find out people who like the new movies of Marvel or DC, or you want to discover the people who just like to eat pizza. The user properties section in your Firebase analytics section can give you up to 25 custom defined user properties.
Firebase already has some pre-predefined user properties, such as user gender, user country, and so on. You can get the list of all the predefined user properties from here: https://support.google.com/firebase/answer/6317486?hl=en&ref_topic=6317484.
Now let's define some user properties. It starts with selecting the wanted application--in my case, it's my Android application, but you can select any of the apps that use your Firebase project--and then adding the user property itself within the Firebase project console. To do so, simply head to your Project...