From the workspace settings, you can manage who can add a member with a paid role or change a member's role from free to paid in a workspace.

To update the workspace settings, click the "Settings" button at the top of your Workspace Members page.

From there, you can access this permission setting under the Workspace tab.

Members can only invite other members at a role level less than or equal to their own role. For example, if you select the Owner, Admins, Editors, and Developers option, an Editor will be able to add a member with an Editor, Developer, or Reviewer role.

If you don't have any seats available for these members with paid roles, Zeplin will give the workspace Owner and Admins a 7-day grace period to confirm or revert these additional seats added. Members who are not reviewed within 7 days will be confirmed automatically, and new seats will be added to the subscription. You can learn more about the grace period here.