Hi there!
Typically, issues like these are caused by a conflicting plugin or theme installed on the site.
In order to troubleshoot this further would you mind taking the following steps?
1. Temporarily switch to one of our default themes, such as Storefront (https://woocommerce.com/storefront/) to ensure that this isn’t a theme compatibility issue. Once you switch themes, can you check and see if everything functions as expected?
2. If not, we also recommend deactivating all plugins except for WooCommerce to see if this resolves the issue at that point. If it does, then you would need to activate each plugin, one at a time, to see if you can find the conflicting extension/plugin.
It is advisable to backup your site content and database before making any changes, and you could also duplicate the site for testing purposes if you don’t want to interrupt the live site.
For a full guide on conflict testing please see:
https://docs.woocommerce.com/document/woocommerce-self-service-guide/
Cheers.