Welcome yahia80,
Thanks for using the Apple Support Communities! We understand that you are looking to find a suitable amount of home internet data to get and you would like to see how much your devices consume. Let’s take a look and see what we can do. We're happy to help!
Natively there is not a current way to view how much data your device is using through your iPhone. Alternatively, if you have current home internet you can try reaching out to your service provider to see if they will share how much home internet data you are using.
We would recommend providing feedback to Apple to suggest and recommend this feature become available in future operating systems.
Provide Apple Feedback
Have a great day and take care!