My iPad is not updating to iOS 15 it says its updated with 14.7

It is likely that you have a device that is NOT compatible with iOS 15. Check to see if your device is or not compatible with iPadOS 15 by clicking on the link below:

iPad models compatible with iPadOS 15 - iPad User Guide - Apple Official Support

With iPadOS 14.7 installed, your iPad is clearly compatible with iPadOS 15.0.

These support pages outline both the available methods by which the update can be performed - and troubleshooting should you experience difficulties:

Update your iPhone, iPad or iPod touch – Apple Support

If you can't update or restore your iPhone, iPad or iPod touch – Apple Support

If your iPhone, iPad or iPod touch won’t update - Apple Support

iOS update and restore errors – Apple Support

If you continue to experience difficulties updating to iPadOS 15.0, you may be more successful if you use a PC or Mac computer to perform the update. You will need access to either a PC (with iTunes installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS). Ensure that your installed version of iTunes has been updated to the most recent version; the essential device drivers are included.

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Update software on iPhone, iPad or iPod touch in iTunes on PC - Apple Support

You should note that for your iPad to install an available update, its battery must be charged to at least 50% capacity - and/or be connected to its Power Adapter. Similarly, the iPad can only be updated over a standard WiFi connection - or be updated by a PC or Mac using iTunes or Finder - over a USB connection.

Check Settings->General->Profile & Device Management, and make sure you don't have an iOS 14 Beta profile installed. If you do, remove it, restart your iPad and try to update again.