Cacher is the code snippet organizer for pro developers

<?php

/**
 * Add 2 new columns to the exported affiliates's CSV file for the affiliates's first name and last name
 */
function affwp_custom_export_affiliates_csv_cols( $cols ) {
	$cols['first_name'] = 'First Name';
	$cols['last_name']  = 'Last Name';

	return $cols;
}
add_filter( 'affwp_export_csv_cols_affiliates', 'affwp_custom_export_affiliates_csv_cols' );

/**
 * Add the affiliates's first and last name to the .csv columns
 */
function affwp_custom_export_get_data_affiliates( $data ) {
    foreach ( $data as $key => $d ) {
        $user = get_user_by( 'email', $d['email'] );
		$data[$key]['first_name'] = $user->first_name;
		$data[$key]['last_name']  = $user->last_name;
	}

	return $data;
}
add_filter( 'affwp_export_get_data_affiliates', 'affwp_custom_export_get_data_affiliates' );