A Workspace is an instance of Yext. There can be multiple users in a Workspace (such as assistants or delegates you've invited to help manage your Yext account) but only one Workspace owner. The name of the Workspace is based on the first social media account that was linked to your Yext account.
To switch between Workspaces, select the drop-down menu with your thumbnail photo. Select the Organization (if applicable) and Workspace.