My Macbook is old and cannot get the recent version of XCode. But my phone is new and it has the new iOS version. For example XCode can support upto 15.2, while my iOS is 15.6.1
The one option is to buy a new computer and install new Xcode so that it can install my apps in the phone.
Easy fix is get the iOSDeviceSupport files
It can be downloaded from the link here
Now download the file that is specific to your phone iOS version.
For example my current iOS is 15.6.1.
So i downloaded the zip file 15.6 and unzip it.
Now use Command+Shift+G in the finder window which will let you directly input path even if it is hidden and take you there.
You want unzipped folder here
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/
this folder will have a folder structure for each iOS it supports. now drop the unzipped folder 15.6 there. restart the Xcode and now Xcode supports 15.6