A quote defines the work that will be delivered to a potential customer and the price is will cost.
In VOGSY, documents for quotes are automatically generated from an opportunity, so they can be sent to the customer. Customers can digitally sign quotes and invoices with the Signhost plugin.
Once the customer signed the quote, you can manage the work you deliver in a project and bill the customer for it with invoices.
A detailed statement of work can be defined in a pending project that is linked to the opportunity. Deliverables and their price will directly be added to the quote that is generated.