When I turn on mobile data then my phone lagg for few seconds

Hi @wasimakram19945

Try starting the phone in safe mode and check if it works OK when enabling mobile data or WiFi i.e. no lag.

If it works OK then a downloaded app (or apps) may be the problem. They may be accessing online data in the background, unbeknownst to you and this slows down the operating system.

A downloaded app is one that you downloaded and installed on the phone and wasn't pre-installed on the phone when you first got it.

Check the permissions of your downloaded apps in Settings > Security > Permissions > Apps