看见register_form 用于修改注册表的操作挂钩

add_action( "register_form", function() {
    $html = \'<p>\'.__(\'Do you want to buy or sell?<br>Choose your role\').\'</p>\';
    $html .= \'<p>\';
        $html .= \'<label for="_customer"><input type="radio" name="user_role" id="_customer" value="customer"/>\'.__(\'Customer\').\'</label><br>\';
        $html .= \'<label for="_vendor"><input type="radio" name="user_role" id="_vendor" value="_vendor"/>\'.__(\'Customer\').\'</label>\';
    $html .= \'</p>\';
    echo $html;
} );

add_action( "user_register", function( $user_id ) {
    $allowed = array( \'customer\', \'vendor\' );
    if( isset( $_POST[\'YourFieldName\'] ) && in_array( $_POST[\'YourFieldName\'], $allowed ) ){
        $user = new WP_User( $user_id );
        $user->set_role($_POST[\'YourFieldName\']);
    }
} );