If you're using Swift Package Manager or the zip file, everything should work for you using Xcode 12.0 or above. See the instructions below for CocoaPods and Carthage.
Starting with Firebase 7.5.0, Firebase supports Apple Silicon Macs via CocoaPods. CocoaPods 1.10.0 is required.
The special M1 versions required for FirebaseAnalytics support for versions 7.2.0 through 7.4.0
are no longer necessary.
XCFrameworks are required to include the arm64 slice for iOS devices and the macOS simulator for Macs running on Apple silicon. Unfortunately, Carthage does not support XCFrameworks yet which prevents us from being able to include support. See Carthage/Carthage#2799 for progress.