Before you remove yourself: if you're the current Workspace Owner on an Enterprise workspace, identify the current owner in User Management and update the successor there before leaving. Workspace Owner is an Enterprise-only role; on other workspaces, give the intended successor Admin access so they can manage workspace users after you leave.
You can request the removal of your account from any workspace admin on a workspace. Workspace admins can remove all levels of users from a workspace except for their own logged in user. Removing someone from a workspace ends their membership in that workspace, but it does not delete their Air account. Here's a step-by-step guide for managing users.
If you're the only user on your free workspace and you need to remove it from your account, follow the steps outlined on this help center article.