How to transform a quotation into an invoice?

It's possible to transform an quotation into an order form, delivery note, deposit invoice or invoice.

For example, to convert a quotation into an invoice, you must:

1. Select the quotation to be invoiced from the “Quotation” menu
2. Click on “Invoice”
   
3. The invoice is created automatically in the “Draft” state, taking all the elements of the quotation. 

It is then possible to modify the elements if necessary.

see the article : "How to create an invoice?"