Clients:Quotes Tab
From WHMCS Documentation
The Quotes tab is accessed via the Clients > View/Search Clients page, select a client, then click the tab marked "Quotes". It contains a paginated list of all the client's existing quotes, icons to edit or delete an existing quote and a button to create new quote.
The number of entries per page is determined under Setup > General Settings. Click the table headings to change the sorting order.