- Get apktool
- Get uber-apk-signer
- Create a signing certificate, this can be done inside android studio or using keytool
- Get your apk of choice from the internet or likewise
- Decompile the app using the following command, substitute the apktool version for what you downloaded.
java -jar apktool_2.6.1.jar d app.apk -r
- Open your text editor of choice in the new directory
app
and edit away, I recommend using jadx-gui for finding stuff to edit.