Weird strange letters appeared in all website links [duplicate]

This has to do with geolocation, and is functionality built into Woocommerce.

https://woocommerce.wordpress.com/2015/07/02/making-geolocation-static-cache-friendly-in-2-4/

See under the title on that page Geolocation, with a hint of Ajax

This seems to be a pretty good write-up of the functionality and how to disable it:

https://www.wpbeginner.com/wp-tutorials/how-to-remove-vxxxx-string-from-wordpress-urls/