You can change these text using translation files or contact woocommerce support.
To change the font size on mobile you may use css code. Provide us with your site URL and let us know what country should we select on cart page to be able to see tax information, we will provide you the custom css.
You can use Loco Translate plugin (Loco Translate > Plugins > Woocommerce > your language > Find and translate needed strings https://prnt.sc/k8b4ub). If this way won’t work, I would recommend you to contact woocommerce support.