Managing member access in a Slack workspace is effectively done through the "Administration" settings located under the "Members" tab. This centralized area allows administrators to add or remove members, adjust roles, and configure settings related to workspace access and permissions. Using this section ensures that all membership-related tasks are streamlined and provides a clear interface for monitoring and managing user access. Administrators can control what each member can do within the workspace, which enhances security and helps maintain a well-organized communication environment. Other options do not provide a comprehensive method for managing member access. For instance, accessing the "Settings" feature under the "Profile" tab pertains more to personal settings for individual members rather than workspace-wide member management. Meanwhile, direct messages to members may facilitate communication but do not impact member access control. Lastly, while contacting Slack support might assist with specific problems, it is not the usual route for typical member management tasks, which can be handled directly by workspace administrators.