If you want to give a supporter, a colleague or client temporary access to a website, without creating a normal user account which you must remember to delete, this plugin is for you.
You can create any number of temporary logins, with any role necessary, and chose any automatic expiration between one hour and months. Send the generated URL to the user via IM or mail, and the user can log in to the dashboard instantly, no password required.
You can enable or disable existing temporary logins from the dashboard, if you want to extend a login period or disable a login before the automated expiry kicks in. A temporary user assigned the admin role, is not allowed to access the user profile or create a new user.
Extract from WordPress.org
Create self-expiring, automatic login links for WordPress. Give them to developers when they ask for admin access to your site. Or an editor for a quick review of work done. Login works just by opening the link, no password needed.https://wordpress.org/plugins/temporary-login-without-password/