In 'Settings/Users/Access Management', enable the right: 'Authorize to make a sale excluding taxes'.

Create the customer of your non taxable sale, and assign him:

• a tax number (or type 'export'),
• and an address outside your country.

Then create a new sale and link it to your customer.
Select his address outside your country for the delivery address.
Click on the 'Duty-free sale' button that appears at the bottom right.

All taxes on your products are canceled.

To print legal information on your invoices, you can:

• complete them in the Note field of the sale,
• and enable the right in 'Settings/Users/Access Management': 'Print sale notes'.