register_helper_with_user_avatar.php

<?php
/*
 * Add WP User Avatar from Register Helper field during checkout.
 */
function my_updated_user_meta($meta_id, $user_id, $meta_key, $meta_value) {
  // Change user_avatar to your Register Helper file upload name.
  if( 'user_avatar' == $meta_key) {
    $filename = $meta_value['fullpath'];
    $filetype = wp_check_filetype( basename( $filename ), null );
    $wp_upload_dir = wp_upload_dir();
    $attachment = array(
    	'post_mime_type' => $filetype['type'],
    	'post_title'     => preg_replace( '/\.[^.]+$/', '', basename( $filename ) ),
    	'post_status'    => 'inherit'
    );
    $attach_id = wp_insert_attachment( $attachment, $filename);
    // Make sure that this file is included, as wp_generate_attachment_metadata() depends on it.
    require_once( ABSPATH . 'wp-admin/includes/image.php' );
    $attach_data = wp_generate_attachment_metadata( $attach_id, $filename );
    wp_update_attachment_metadata( $attach_id, $attach_data );
    update_user_meta($user_id, 'wp_user_avatar', $attach_id);
    
  }
}

add_action('added_user_meta', 'my_updated_user_meta', 10, 4);



// REGISTER HELPER
function my_pmprorh_init()
{
	//don't break if Register Helper is not loaded
	if(!function_exists( 'pmprorh_add_registration_field' )) {
		return false;
	}
	$fields = array();
	$fields[] = new PMProRH_Field(
		'gender',						// input name, will also be used as meta key
		'select',						// type of field
		array(
			'required'  => true, // make this field required
			'options' => array(				// <option> elements for select field
				''		=> '',			// blank option - cannot be selected if this field is required
				'Male'	=> 'Male',	// <option value="lessthan2000">&lt; $2,000</option>
				'Female'	=> 'Female',	// <option value="2000to5000">$2,000-$5,000</option>
			)
		)
	);

	$fields[] = new PMProRH_Field(
		'birth_date', //
		'date', // type of field
		array(
			'label'     => 'Birth Date:', // custom field label
			'required'  => true, // make this field required
			'profile'   => true, // show in user profile
			'memberslistcsv' => true, // Uncomment to Include in Member List CSV Export
			// 'addmember' => true, // Uncomment to display in Add Member
		)
	);

	$fields[] = new PMProRH_Field(
        "user_avatar",              // input name, will also be used as meta key
        "file",                 // type of field
        array(
            "label"=>"Member Photo",
            'required'  => true, // make this field required
            "profile"=>false,    // show in user profile
        ));

	//add the fields into a new checkout_boxes are of the checkout page
	foreach($fields as $field)
		pmprorh_add_registration_field(
			'checkout_boxes',				// location on checkout page
			$field						// PMProRH_Field object
		);
	//that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action( 'init', 'my_pmprorh_init' );