There are 3 type of users for Jira Service Desk projects.
Customers: These are non-licensed users who create requests through the customer portal.
Agents: These are licensed Jira Service Desk users who works on customer’s requests. They can perform any function on the normal issue view as long as you give them permission through project’s permission schema.
Collaborators: These are non-agent users. They are licensed users for Jira Core or Jira Software but not for Jira Service Desk. They have limited permissions for issues belonging to a service desk project. They may not perform certain operations on a service desk issue, such as “Logging Work”, “Transitioning Issue” etc. even if you configure project’s permission schema and give them permission to “Work on Issue” they will not able to “Log Work” for a service desk issue.
From 3.9.0 version of WorklogPRO, it will allow collaborators to work on issue if they have given permission through project’s permission schema. You don’t need to configure any WorklogPRO specific feature as long as you have give correct permission in project’s permission schema.