Can the Airtag be set up on multiple devices?

COULD WE FIND ONE AIRTAG FOR THE TRAVEL DOCUMENTS, OR A CAR FROM TWO FAMILY DEVICES ?

I MEAN BEING ABLE TO LOCATE ONE AIR TAG FROM TWO DIFFERENT DEVICES BELONGING TO TWO DIFFERENT ACCOUNTS/INDIVIDUALS BUT FAMILY MEMBERS

Chattanoogan, that's not true with regards to AirTags on MacOS. According to Apple, you can use FindMy on Big Sur 11.1 to locate an AirTag: https://support.apple.com/en-us/HT211331

Obiviously you cannot do "Precise Location" finding with MacOS because the hardware is not there on any Apple MacOS device (yet) for that. But you can use it to do all other FindMy activities with the AirTag, such as finding it's general location and getting it to play a sound if you're nearby.

Airtags paired to an iOS device can be located using FindMy on other iOS devices signed-in with the same AppleID.

They are not “locatable” using FindMy on a Mac (Big Sur) signed-in with the same AppleID.

They are not “locatable” by shared family members.

Thanks, but when I went to look on my Mac this AM … voilà … my airtags were all correctly located.

Don’t know if it was something in the last couple of BigSur updates, or planetary alignment; but all seems to performing well now.

I HAVE however noticed that our iPhone 6s and Xs do NOT provide the “unaccompanied airtag tracking warning” per Apple’s literature. (although the tags themselves DO beep when moved if their paired device is “elsewhere”)

(Meanwhile, a friend’s iPhone 12 does indeed “alert” per description in the literature)

Perhaps that particular feature is hardware dependent (e.g. needs UWB perhaps ?)

I believe the AirTag is associated with your AppleID / iCloud account, so it shouldn't matter which device you use, as long as they're all logged in with the same AppleID.

You are 100% correct; that piece of my post was in error (but discovered too late to correct w/ edits).

[Still trying to determine why my own airtags aren’t reflected on my Big Sur MBP] 🤔

My condolences. Good luck.