What the purpose of Project Quotation

Hi Experts,

I am doing setup for Fixed-Price Project. I want to know what is the purpose of Project Quotation. When I created Project Quotation I linked to Project ID. What is the Purpose of linking Project ID.

If project is Fixed-Price. Where do I put agreed total project amount in Fixed-Price Project or Project Contract.

How Project Quotation value with matching with invoice.

If we use Product Configurator for Project Quotation than how to invoice for Project type Fixed Price.

I am new for Project. But I read Microsoft material.

Hoping for reply.

Thanks,

Faiz