As others already pointed out you can use SharedPreferences generally but if you would like to store data encrypted it's a bit inconvenient. Fortunately, there is an easier and quicker way to encrypt data now since there is an implementation of SharedPreferences that encrypts keys and values. You can use EncryptedSharedPreferences in Android JetPack Security.
Just add AndroidX Security into your build.gradle:
implementation 'androidx.security:security-crypto:1.0.0-rc01'
And you can use it like this:
String masterKeyAlias = MasterKeys.getOrCreate(MasterKeys.AES256_GCM_SPEC);
SharedPreferences sharedPreferences = EncryptedSharedPreferences.create(
"secret_shared_prefs",
masterKeyAlias,
context,
EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
);
// use the shared preferences and editor as you normally would
SharedPreferences.Editor editor = sharedPreferences.edit();
See more details: https://android-developers.googleblog.com/2020/02/data-encryption-on-android-with-jetpack.html
Official docs: https://developer.android.com/reference/androidx/security/crypto/EncryptedSharedPreferences