Does site access to a user mean that they can access JIRA service desk and see all the projects?

[Fahad Akhtar]

When I go to user management as an Org and Site Admin, I see a list of a lot of users, almost 4 pages worth. But I think only 14 of them are users because only 14 of the 25 licenses have been used up. Next to each name under the column status it says "site access". What is site access? And are there other options besides "no site access" and "has site access"? I want to make sure that these customers only see the projects that they are a part of. Thank you.

[Michael Kuhl {Appfire}]

Hi Fahad - Site access simply means they can access the site.  Both Service Desk customers and users need Site Access. 
Access to projects is controlled by project settings.  Here's a guide from Atlassian to learn more.