How can i do to autolock during call in samsung galaxy tab a8.0?

[AC Question]

My tablet was disable double tap lock during call

 

[B. Diddy]

Welcome to Android Central! You were making a call using a Tab A? Was this a VoIP call using something like Skype?

I don't quite understand your question -- are you saying that there's a "double-tap to unlock" screen while you're on a call? This is usually present if (a) the device doesn't have a proximity sensor (and therefore the screen won't automatically turn off when the phone is held up against the ear), or (b) if you've disabled the "Turn off screen during call" option in some Phone apps.