If you want them to co-author the copilot along with you, then yes they would need license but if it's just for testing, I will be showing you what I do usually in this scenario:
- In the channels tab, select teams.
- In that panel, select "turn on Teams"
- After that, edit the details of your agent as needed.
- You'll notice a button called "availability" click on it.
- Now you can add them and give them view access. Make sure to tick "email new users" below before sharing.
- In case they did not get email, from the same 'availability' tab, you can copy link and give them.
Now they can use your agent through teams.