Add code to your child theme’s functions.php file or via a plugin that allows custom functions to be added, such as the Code snippets plugin. Avoid adding custom code directly to your parent theme’s functions.php file as this will be wiped entirely when you update the theme.
Use the following code to change the number of WooCommerce products displayed per page.
This requires you to have your shop page display, which can be found in customizer view under WooCommerce > Product catalog set to “Show products”
https://gist.github.com/woogists/e414d9463d8843bbe4efc4c4c519d888