Hi there ??
At the moment, there’s no default option for that in WooCommerce, and setting that as the default would require quite a bit of additional coding. Please kindly note that this requires some custom coding – which goes beyond the scope of support we are able to provide in this forum.
However, upon checking on the internet, it seems that this guide might work for you:
https://quadlayers.com/disable-woocommerce-postcode-validation/
If you do require more help with the actual coding, we’d recommend you hire a developer who can take a look at this, quote you for their services, and help you add this feature to your site. We’d recommend getting in touch with a web developer or one of the customization experts listed at https://woocommerce.com/customizations/.
Cheers! ??