Which language is the best for making apk???

Answer 1

kotlin or java

Answer 2

Kotlin or Java.
Formerly, Google used mainly Java for Android App development, but in 2019, Google announced Kotlin as its official language for Android dev. Just learn kotlin, because it is easier, more concise, less prone to errors and exceptions, and a bit faster than Java.
Check this link out:
https://developer.android.com/courses