Add "Other amount" in checkout

I need to add "Other amount" to the checkout (shown in the image)
I use a plugin named Woocommerce upsell to show these amounts in checkout and also a plugin named "Name your price" to give the option to a product to have open amount.

https://tiendahogardecristo.cl/wp-admin/admin.php?page=woocommerce-checkout-upsell-funnel#rule