ProfilePress include a user moderation module for approving new registered users, blocking and unblocking users account in WordPress.
To activate this feature, click the Extras ProfilePress menu and activate it in User Moderation section.
After activating this feature, new users accounts will be in
pending mode until the account is approved by an admin.
When a user's account is approved, blocked or unblocked; an email notification is sent to the user to that effect.
The notification message is fully customizable at ProfilePress Settings plugin page.
To get notified when a user is pending approval; still on User Moderation section, scroll to Admin Notification When a New User Is Pending Approval sub-section and customize the email notification as you deem fit.