I use SecScanQR, which is great for translating QR-codes to and from text.  It also works for other kinds of barcodes.

You can get SecScanQR here:  https://f-droid.org/en/packages/de.t_dankworth.secscanqr/

That's in the F-Droid repository, a huge repository of free and open source apps for Android.  If you're looking for Android apps that don't track you and don't have other anti-features, F-Droid is a great first stop!

Cheers,
Owen