Can I change the permalink of the product and put a password?

(1) A product's permalink can only be changed by the website admin. To do that, you would go to Products in the backend, click on the product, and click here on Edit:

Alternatively it could be possible for us to add a code snippet to automatically remove certain characters from the title, so for example to remove Japanese characters or replace them with something. But we would need a specific algorithm / logic to do it.

(2) With our B2BKing plugin, ( https://kingsplugins.com/woocommerce-wholesale/b2bking/ ), you can make it so that only logged in users can open products, or that they need to login first to see the shop, or to see prices.

Otherwise the only option is with dedicated plugins, such as https://wordpress.org/plugins/password-protected-woo-store/

Kind regards,

Stefan