When you access a borrower's account by scanning their library card barcode or by searching by name, any available holds will be displayed on the default landing page. After the account has been accessed, you can also view all active Requests and Holds by opening the Borrower Request List window by selecting Borrower > Requests from the top menu.
From this window you can see the status of active Requests and Holds, cancel requests for the patron, or suspend the request until after a certain date (for example, if a patron wants to maintain their position in a queue for a requested item but is scheduled to take a vacation, you can suspend the hold until after a specified date has passed - this will allow other patrons later in the queue to borrow the item in the meantime).
Video: View Requests by Borrower or Title
Expired Holds
By default items are held for 7 days, after which they should be checked in again. If another borrower has a requested the item, then Horizon will tell you to hold it for them.
You can view the list of expired holds by going into Circulation Reports and selecting from top menu Request > Expired/Canceled. See the section Reports in the Horizon Guide for more details.