Always send the checkout_free confirmation email in PMPro when changing a user's level in the admin dashboard.

my_send_pmpro_confirmation_emails_from_dashboard.php

/**
 * Always send the checkout_free confirmation email
 * when changing a user's level in the admin dashboard.
 */
function my_send_pmpro_confirmation_emails_from_dashboard( $level_id, $user_id, $cancel_level_id ) {
	// If we're not in the dashboard, this is probably a checkout on the frontend
	if ( ! is_admin() ) {
		return;
	}
	
	// If you want to exclude certain level ids, add them here.
	$excluded_level_ids = array();
	
	// Send email if level > 0 and is not excluded.
	if( !empty( $level_id ) && ! in_array( $level_id, $excluded_level_ids ) ) {		
		$email_user = get_userdata( $user_id );
		$membership_levels = pmpro_getMembershipLevelsForUser( $user_id );
		
		// In case of MMPU, let's find the specific level we're wondering about
		foreach( $membership_levels as $membership_level ) {
			if ( $membership_level->id == $level_id ) {
				$email_user->membership_level = $membership_level;
				break;
			}
		}		
				
		$pmproemail = new PMProEmail();
		$pmproemail->sendCheckoutEmail( $email_user );
	}
}
add_action( 'pmpro_after_change_membership_level', 'my_send_pmpro_confirmation_emails_from_dashboard', 10, 3 );

This recipe is included in the blog post on "Send Members a confirmation email when admins change their membership level." at Paid Memberships Pro here: https://www.paidmembershipspro.com/send-members-a-confirmation-email-when-admins-change-their-membership-level/