Copy this this on your choosed templates.
Locate a file code :
locate_template( array( 'function-custom.php' ), true );
Require a file code :
require_once( 'functions-custom.php' );
Include a file code :
include( 'functions-custom.php' );
Get template functions-woocommerce.php
Ex: get_template_part( ‘partials/content’, ‘page’ );
get_template_part( 'functions-woocommerce' );