Code example of how to resend all messages of a form from Caldera Forms See: https://calderaforms.com/doc/resend-caldera-forms-messages/

resend_all_saved_message.php

<?php
add_action( 'init', function(){

	//This is a key to track which page were on of resend using option table
	$page_key = '_my_cf_resend_page_key';

	//Get current page of entries to resend
	$current_page = get_option( $page_key, 1 );
	if( 0 == $current_page ){
		//stop beacuse we're done.
		//probably should remove this code now
		return;
	}

	//IMPORTANT: Update to match your form ID
	$form = Caldera_Forms_Forms::get_form( 'CF59442cd3f31d9' );

	$entries_object = new Caldera_Forms_Entry_Entries( $form, 5 );
	$entries = $entries_object->get_page( $current_page );

	if( empty( $entries ) ) {
		update_option( $page_key, 0 );
		//All done!
		return;
	}

	/** @var Caldera_Forms_Entry $entry */
	foreach ( $entries as $entry ){
		$entry_id = $entry->get_entry_id();
		$resender = new Caldera_Forms_Email_Resend( $entry_id, $form );
		$resender->resend();
	}

	//mark page as 1 more
	update_option( $page_key, $current_page + 1 );

});