Hi shrabin, in S series and A series you can't find native app lock like other company do. But you can use in-app app lock like whatsapp, telegram and signal offers. If you trying put app lock for some other apps, you can try secure folder which is b...

I think it will not work for cellular, only for the third-party applications. I tried but not able to do that

You welcome bro, I understand your happiness after issue resolved, i also did same mistake when try voice changer for first time 

Okay bro 

Is it resolved?