You can share any diagram with other users if you wish to invite them to collaborate on the process (subject to access right restrictions). Just click on the share button in the upper-right screen of the diagram editor.
NOTE 1: If you want to import large groups of people to a Space or want to setup users without inviting to specific content, see this article to "Invite or Import users to the Space"
NOTE 2: if you cannot see the share button, you are in your Personal Space. You need to be in (or create) a Team Space for collaboration. See this short video snippet if you don't have a share button:
NOTE 3: make sure the top panel is not hidden: you can hide/show the top & right panel with a blue arrow buttons.
You will see a dialog window where you can specify the user you want to share the diagram with (either by selecting an existing user or providing a new email address), and add a message if you want to. If you want to share the diagram with more than one user, click "add another user" (up to 10 users at a time).
Note: you can keep adding multiple blocks of 10. If large numbers of users, you can add through CSV import to Space.
Users you shared the diagram with will receive your message, link to the diagram, instructions for how to access it in the future, and registration tips if they are not yet Elements users. They will also receive an attached screenshot of the process diagram (email screenshot as seen in gmail).