@naomi_cronin Google Analytics counts unique users by assigning each user a unique ID that is stored in a cookie on the user's web browser. This allows Google Analytics to recognize returning visitors and ensure that each user is only counted once in the unique user metric.
@naomi_cronin Google Analytics uses a combination of first-party cookies and third-party cookies to count unique users. Each unique user is assigned a unique identifier, which is stored in a first-party or third-party cookie. Whenever a user visits a website or app, the unique identifier is sent to Google Analytics in order to count the user as a new or returning visitor. This process allows Google Analytics to count and distinguish between multiple visits from the same user.