Multisite distinguishes user registration from site registration. A private agency network may allow neither, while a publishing community may allow approved users without allowing them to create sites. Record who approves access and how unwanted registrations will be handled before enabling an open signup process.

1. Open Network Admin > Settings > Network Settings as a Super Admin.
2. Review the Registration Settings options and choose whether registration is disabled, users may register, logged-in users may create sites, or both are allowed.
3. Review registration notifications, permitted or banned email domains, and reserved site names where relevant.
4. Save the settings and test the registration page from a logged-out browser.
5. Test a normal existing user's ability to create a site if that is part of the selected policy.

No. Registration controls future signup through the applicable workflow. Existing accounts and site memberships need a separate access review. Do not bulk-delete users as a substitute for closing registration, because they may own content or have legitimate membership on another subsite.

A membership, commerce or integration plugin may have its own account-creation workflow and permissions. Review those settings independently and test the actual public forms. Network registration settings are not a complete inventory of every system capable of adding users.

Use appropriate verification and rate controls for an intentionally public registration service. Monitor new accounts and sites for abuse and keep notification mail deliverable. Do not treat an email-domain allowlist as proof of a person's identity or authority to administer a site.

Check that legitimate users understand how to request access when open signup is closed. Confirm that administrators can still add approved users through the intended workflow and that password reset remains available. Keep a record of the selected policy and review it when new plugins introduce registration, checkout or community features.

• Adding an existing network user to another subsite
• Adding a new site to an existing WordPress Multisite network
• Planning backups for a WordPress Multisite network
• Archiving a Multisite subsite instead of deleting it
• Setting Multisite upload limits and allowed file types

• WordPress: Settings
• WordPress: Admin
• WordPress documentation