the control is not available because you do not have the correct permissions sharepoint.

While working with any Approval of document with Sharepoint Designer workflow , I came accross this issue for the people picker field.




"The control is not available because you do not have the correct permissions"

This issue occurs when User creates a group and "Who can view the membership of the group? " to Group Members.

To reolve this issue update "Who can view the membership of the group? " to Everyone.

PLEASE REMEMBER: 
Go to Site Settings -> People and Groups -> Click Groups -> Settings -> Group Settings -> Change 'Who can view group membership?" to be Everyone and always.