Air tags using a computer iPad Pro

Hi I am wondering what are tags, what do they look like, what can they do? Why don’t they seem to work at great distances? Read it is used to track, children, dogs, cats, computers and cars. Why isn’t is working correctly and which products support it? How many of those things do you get? What else can they do?

Never heard of the word tags until I read it here.

thanks community for any answers I get