A name tag is a small piece of card or plastic that you wear on your clothes to show your name, especially at a work event or conference. Full definition
Each guest knows where to sit when chairs are marked with name tags. (bhg.com)
I would have used the ones I saved from last year, but I used those for name tags on presents this year. (theinspiredroom.net)
She had a strict, no - cellphone rule on set, and she encouraged people to wear name tags so that cast and crew could get to know each other. (avclub.com)