Add parameters to the current url

Wordpress allows to add one or more parameters to the current url or external url by using following function. This function returns a modified URL query string.

add_query_arg()

There are 2 ways to use this function

1. single key and value

add_query_arg( 'key', 'value', 'http://example.com' );

      2. Associative array

add_query_arg( array(
    'key1' => 'value1',
    'key2' => 'value2',
), 'http://example.com' );

How to add parameters to the current url

Here get_permalink function returns a URL query string of current url.

add_query_arg( 'key', 'value', get_permalink() );

How to add parameters to the post/page url

get_permalink is used to get post / page url based on post / page id.

add_query_arg( 'key', 'value', get_permalink('10') );