Firebase is a Google product that simplifies the development of mobile apps by providing out-of-the-box solutions for common mobile development tasks. Internally, we use Firebase to send and receive push notifications in our mobile apps. Due to the way Firebase works, it's necessary to create a separate account and Firebase "project". So, the first step to enable push notifications in your white label app is setting up a Firebase account and project for your app. Firebase is completely free.
Navigate to https://firebase.google.com/ and sign in in the top right hand of the page.
After creating an account and signing in, create a project by clicking the "Add Project" button.
Fill out the highlighted fields in the window that pops up. Name your project anything you want. Click the "Create Project" button.