From the customers page, in any list view (Recently Viewed, Recently Added, Accounts, Locations) you have the option to display or hide Deactivated accounts.

If you use the search bar from any of these views and search an account, it will match the setting you have toggled on for deactivated view.

If you have selected to Show Deactivated accounts, they will populated in the matched list, highlighted in Orange to indicate deactivated

If you have selected to Hide Deactivated Accounts, they will not populate in the matched list.