As I mentioned above, you won´t be able to create an offer. So, if you are a company that supplies goods, services or anything else, and your customer has to approve your offer first, so for you is this Sales Module meant. 
The Sales in Odoo is like any other module connected to other modules. You find there a connection to CRM into the customer database; you see orders, products, price lists, connection to billing etc. 

What can come in handy in Sales?

Who you are selling to – quick click into CRM and contacts

It makes easier you work with Customers; in CRM you see all contacts or only those which are marks as Customer. In addition, you can limit some users on their rights so they see only their contacts.

What you are selling – Creation of products and their variants

You have to establish your products and price lists, so you can sell. The product can be a good, service or a product. It doesn´t matter, if you are selling tea leaves, produce custom-made machines or provide consultancy. 

Every type of Product has its specifics. The product has to have a piece list (what parts and how many of them is necessary for one product), the service requires timesheets, the products are just bought and sold with a margin. 

Every product can have its variations. You hardly sell a pullover; you are selling a pullover in the size from S to XL. So you have X variations of a product. If you put colours to it, new combinations are created.

For how much are you selling – Pricelists 

The pricelists in Odoo works on the principle of heredity. It means that if you create one main price lists, the others result from it. So, if you create a sale 10% on everything, or you just determine certain categories or products for the sale. If you use your pricelists in another currency, they can be automatically converted. Individual pricelists are set to individual customer and you can start selling. 

Offers

Now we know to whom and for how much we are selling, so we can start creating the offer. If we sufficiently filled information about the customer, so the part of data will be filled automatically: the billing address, delivery address, the type of pricelist and due date. Then you have to fill the selling items.

The offer will be exported into .pdf or it can be sent directly from Odoo on the customer´s email address. The customer can accept the offer – then an order is created, or it can be an edit (add a sale, add or remove items or the amount of a given item) and then it is given to the customer for approval. Of course, we can even cancel the offer and end the whole process.

Offers can be filtered according to the user who created it, according to the customer of the status of the order and many other attributes

Connection to the stock, billing or production

If you are selling a good or a product, the Sales module is connected to the Stock and Production. In praxis, it means that in the background, the removal order is created to a given order and the warehouseman prepares the goods. Or that a production order is created for the good in the order that contains the list of the parts which are needed for the production of the good. At the same time, the system watches supplies, reserves material etc.