Data turned off

Hey there, Reemmashraqi.

Welcome to the Apple Support Communities! I'd be glad to see what I can do to help you out with making sure that your cellular data settings behave how they're configured to.

You mentioned that the setting for your cellular data turns off by itself. Does this happen randomly, or is there a specific event or happening that occurs each time this presents itself? For example, does it happen every time you use a certain app, every time you leave a Wi-Fi network, or in any other specific instances? While testing this, you'll want to make sure you remove any accessories or protective cases, just to make sure that isn't part of the problem. Let's also make sure that your iPhone is fully updated to the latest version of iOS compatible by following the steps in Update your iPhone, iPad, or iPod touch.

Also, let's make sure that you've got the latest carrier bundle as well. More info on checking that can be found in Update your carrier settings on your iPhone or iPad.

After following those steps, give it a try and report back what you find out.

Take care.