Not able to update in iPad 7th gen.

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

What iOS/iPadOS version is this iPad, currently, running?

What is the rated, internal data storage space model of your iPad and how much of this free, internal data storage capacity is left inside of your iPad model?

14.4 is supported by that model.

What happens when you try?