The Quick Search and A-Z Search makes it quicker to find the Record that you would like to view.
Your system administrator can select in AppStudio which Fields are searchable when using the Quick Search feature. You will then be able to filter down the Records in this list by Records that contain the text in any of the Fields that have been selected as searchable. These are commonly the Record Title, values that appear in selection Fields and other Key information.
The Quick Search will be applied in addition to any filters that you already have applied. In the example above the records have been filtered down by 'Status' to Amber and then also by the Records that contain the text 'New' in the Title.
Note: The Quick Search filter criteria will persist when changing the filter until you navigate away from the report that you are viewing.