The easiest way to find a case record from case list is by using the Quick Find function labelled as “Look for” and located as single text field above the Case list (or any other entity list)

Quick Find finds only active records. You can customize the fields searched in the Look For field by adding the field as a search column to the Quick Find view for the entity. The Quick Find view is located in Settings>Customization>Case>”Forms and Views”>”Quick Find Active Cases”

Click: “Add Find Columns” and select to columns to be searched