An example of how to pull in the latest approved registration details across all events.

functions.php

<?php
function latest_reg_details() {

	$query_params = array(
		array(
			'STS_ID' => EEM_Registration::status_id_approved 
		),
		'limit' => 1,
		'order' => 'DESC'
	);


	$regs = EEM_Registration::instance()->get_all( $query_params );

	$registration = reset($regs);

	if ( $registration instanceof EE_Registration ) {

		$attendee = $registration->attendee();

		if ( $attendee instanceof EE_Attendee ) {
	
			/* Here you have access to the EE_Attendee object for the latest 'Approved' registration */
			// Kint debug
			// d($attendee);


			//Get the full name of the attendee.
			$name = $attendee->full_name();

			//Get the event from the registration.
			$event = $registration->event();

			//d($event);

			return $output = 'Join ' . $name . ', who registered onto ' . $event->name();
			
		}
	
	}

}
add_shortcode('LATEST_REGISTRATION_DETAILS','latest_reg_details');