If you're sharing App-less Access, a 7-digit code is shown on your dashboard after you complete the sharing process. You need to share this code with the person you’ve shared the key with in order for them to use App-less Access.
(You can get a new code by clicking on the key in the Users & Keys page or in the Doors page and the Key Details window will pop up.)
If you're using App-less Access, the 7-digit code should have been sent to you by the person giving you access. You’ll receive a separate email that will contain a link which will take you to a page that asks for a 7-digit code.