In 'Settings/Users/Access management' enable the right:
'Create and modify a quotation'

In the Sales tab, you will find a new section: 'Quotations'.

Click on the top right button ‘New quotation’ to create a quotation.
A quotation works like a sale: you can link it to customer, add products, discounts, notes and a personal reference.
Products added to a quotation are not withdrawn from your inventory. So you can add products out of stock from your product database.

You can print your quotation on a default PDF template.
If you want to use your own custom template, you must use the PDF documents application in the Apps section of your account. This application enables to create specific templates you can use in your sales and quotations. More information.

To convert a quotation into a sale, click on the 'Convert into a sale' button.
The new sale will appear among the parked sales.
Products in stock will be automatically removed from your inventory. Products unavailable (out of stock) will remain pending processing. When these products will be back to stock, select each product line in the sale and click on the 'Withdraw from inventory' button.
A sale can be closed only when all products are removed from your inventory.

You can link your quotations to a status (ex: in process, approved, denied…) with the sale tags.