Add the entry ID on CSV Entries export

cf-entry-id-column.php

<?php

// Based on https://calderaforms.com/doc/caldera_forms_admin_csv/
add_filter( 'caldera_forms_admin_csv', function( $csv_data, $form ){

	//IMPORTANT change form ID to match your form
	if( 'CF5eb5616ea264f' === $form[ 'ID' ] ){
		//Add a header for new column
		$csv_data[ 'headers' ] = ['entry_id' => 'Entry ID'] + $csv_data[ 'headers' ];
		//Add a value for each row for this new column
		//Use the index of array whicj corresponds to Entry ID
		foreach ( $csv_data[ 'data' ] as $i => $row ) {
			//Add the column in data
			$row = ['entry_id' => strval($i)] + $row;
			$csv_data[ 'data' ][$i] = $row;	
		}

	}

	return $csv_data;
	
}, 10, 2 );