Do I have to pay an extra Zoho One License to add a Contarctor User in Projects?

Do I have to pay an extra Zoho One License to add a Contarctor User in Projects?

My company is using Zoho One.

I would like to add some external Contractors that will work with us for a few months to our Zoho Project. They work for a different company and their email address has a different domain.

Do I have to pay extra licences for them?