An "inactive" Party can be identified as having the "Active" selection unchecked within the Party Profile record. 

When a Party is "inactive" it will no longer show in the Party's main grid. In order to view all "inactive" Parties, the user has to run an
Advance Search. 

In the Advance Search, to find a specific "inactive" Party, the user can enter the Party's name and remove the "Active" selection check. 

To find all "inactive" Parties, remove the "Active" selection check and run the search.  

For more information about the Advance Search functionality, please reference the following video: