The Summary tab in the Client Profile contains an overview of the client's details, billing and service information, and management quick links. Invoice and quote PDF files use a template file system. If you use a self-hosted WHMCS installation, you can use this templated system to customize your PDF invoices and quotes. The Quotes tab in the Client Profile lists the client's existing quotes and allows you to edit them or create a new quote. The Invoices tab in General Settings allows you to configure how WHMCS generates and sends invoices and applies late fees. How to troubleshoot question marks replacing text in PDF invoices and quotes. Quotes allow you to send estimates to customers. If the customer accepts your quote, you can easily convert the quote into an invoice.