What makes a good quotation
A good quotation leaves nothing to guess. Describe each item or piece of work clearly, give the quantity and unit price, and show the VAT separately so the customer sees the total they will actually pay. Add a validity date so an old price cannot be claimed months later, and put your payment terms, delivery time and any exclusions in the notes. Professional layout matters too: a branded PDF with a number and date is easier for a customer's purchasing team to approve and file.
Quotation, estimate, proforma, invoice
A quotation is a fixed price offer for a defined job. An estimate is a best guess that may change. A proforma invoice is usually sent once the customer has decided, often to arrange advance payment or import paperwork. An invoice, or a tax invoice if you are VAT-registered, asks for payment for a supply that has happened. A quotation is not a tax invoice and does not create any VAT liability; you charge VAT on the invoice you issue later.
Tips to win more quotes
Reply fast, because the first clear quote often wins. Keep your numbering consistent, QT-0001, QT-0002 and so on, so you can follow up by reference. Offer options where it helps, for example a standard and a premium line. Follow up a few days before the validity date ends. And keep the customer's data private: this tool never uploads your quotes, so your prices stay between you and your customer.