In Odoo, a Quotation and a Sales Order are two distinct documents used in the sales process. Here are the main differences between them:

1. Purpose: A Quotation is a document that is sent to a customer to propose a price for goods or services. A Sales Order, on the other hand, is a document that confirms the customer's request to purchase goods or services.

2. Legal Binding: A Quotation is not legally binding and can be revised or rejected by the customer without any obligation. In contrast, a Sales Order is a legally binding document that outlines the terms and conditions of the sale, including the price, delivery date, and payment terms.

3. Status: A Quotation has a status of 'Draft' until it is sent to the customer, at which point it becomes 'Sent'. A Sales Order, on the other hand, has a status of 'Confirmed' once it has been approved by the customer.

4. Modification: A Quotation can be modified by the salesperson before it is accepted by the customer. In contrast, a Sales Order cannot be modified once it has been confirmed, unless both parties agree to the change.

5. Follow-up: A Quotation requires follow-up action from the salesperson to convert it into a Sales Order. Once a Sales Order is confirmed, it does not require any follow-up action unless there are changes to the order.

In summary, a Quotation is a proposal document that outlines the proposed terms and conditions of a sale, while a Sales Order is a legally binding document that confirms the customer's request to purchase goods or services.