Hi Anne,
Many now use lanyards like this https://lanyardsfactory.com.au/all-in-stock-products/double-clip-lanyards?gad_source=1&gclid=CjwKCAiA_aGuBhACEiwAly57MamSYkYFQ0jxRnlZxiyxZstvLiSu4qYABf31eDgyrY3KIt_oAWZoNRoCWLMQAvD_BwE
You can print their names on carboard and insert into sleeve.
If you have a person on the door when attendees are leaving many people will give back the lanyard and you can reuse for the next event.
Hope this helps
Blessings