Add Custom Currency

Hi,

I am using WP-Deals on my site, and I want to add custom currency.
I know that it can be added via this code:`add_filter( ‘deals_currencies’, ‘add_my_currency’ );

function add_my_currency( $currencies ) {
$currencies[‘ABC’] = __( ‘Currency name’, ‘wpdeals’ );
return $currencies;
}

add_filter(‘deals_currency_symbol’, ‘add_my_currency_symbol’, 10, 2);

function add_my_currency_symbol( $currency_symbol, $currency ) {
switch( $currency ) {
case ‘ABC’: $currency_symbol = ‘$’; break;
}
return $currency_symbol;
}`

found at: https://wpdeals.me/wordpress-deals-codex/snippets/create-a-custom-currency/

But there is no information on which file i should add this code. Kindly tell me the name of file to edit with this code thanks.

https://www.ads-software.com/extend/plugins/wp-deals/