Associate (add) contributors to a requirement

In the requirement details window, click on the Add button and select Contributors from the drop down. In the pop-up, click on the project members name to select and click Add to finalize. If a user is not appearing in the list of available users to add, check the following:

• User to be added as a contributor is a member of the project
• User to be added as a contributor is not already added as a co-owner to the requirement version. Co-owners will need to be removed as a co-owner before being added as a contributor.
• User adding a contributor has permissions to view the appropriate set of project members

If adding the same contributors to multiple requirements, the Group Actions feature may be used. 

Requirement owners, requirement contributors, and co-owners of that version may associate contributors. A user must have view and edit permissions in requirements to do this. Depending on the settings of the user's project permissions, they may be able to view all the project requirements or just a subset of them. The same is true for viewing the list of project members when adding contributors. Users added to a specific requirement as a contributor/reviewer/co-owner will be able to view it.