Why don't apps on my iPad delete?

Go to Settings > Screen Time > Content & Privacy Restrictions > iTunes & App tore Purchases > Deleting Apps and choose Allow.

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Delete apps on your iPhone, iPad, and iPod touch - Apple Support

Assuming that your iPad is not centrally managed by an Educational Establishment or Business (as the device may be remotely managed) - if you are experiencing difficulties with adding, updating or removing Apps from your iPad, you’ll need to check your ScreenTime restrictions:

• Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Adding Apps - set to Allow
• Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps - set to Allow
• Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > In-app Purchases - set to Allow