Edit access can be granted without a license, and can also be given to users outside of your organization. I wouldn't necessarily recommend that for the record, but if you need to give them edit access I would recommend the "Editor - Cannot Share" permission so they don't share your workspace out beyond the scope you approve of. Just open the workspace you want to share, in the top left click the Share button, and enter the email of the client who needs access and you should be good to go.