How to build In app file upload

Hi all,
I am working on building a new app and I am having trouble coming up with the code necessary for someone to upload a file in app. Does anyone know how to build something where the app user can upload a file which goes to the firebase database? Or anywhere where I can learn this?

upload a file which goes to the firebase database

You should better visit the Firebase documentation site. Or find a community site for Firebase.
Firebase is not a framework of Apple's and not preferred to be discussed here.
How to build In app file upload
 
 
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