Allow add terms for attributes

I want to let some site users who can sell products add their own values to existing attributes.
The custom attributes are not interesting because they cannot participate in the product filtering system.
How can a store manager (user) be allowed to create new terms (values) for attributes themselves?
What rights should be allowed?

• This topic was modified 1 year, 9 months ago by cousinr.
• This topic was modified 1 year, 9 months ago by cousinr.