See AirTag on iPhone and ipad

Assuming that both your iPhone and iPad are signed-in to iCloud with the same AppleID, your AirTag should be visible on both devices using the Find My App:

Locate an AirTag or other item in Find My on iPad - Apple Support

You should note that while your AirTags and other items should be visible via the Find My App, precision finding is only available on supported models of iPhone equipped with the U1 (UWB - Ultra Wide Band) chip.

Set up your AirTag using your iPhone, iPad, or iPod touch - Apple Support

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