Hello @leomarioto,
I understand the card fields are not visible.
Can you switch temporarily your site theme to Storefront? Does it work? If so, it is related to the current theme your site is using.
If not, the next step is to temporarily disable all plugins except WooCommerce and Stripe, and check again to see if it is working. If working, you can re-enable the plugins one by one, until you find the cause of the issue.
Be sure you have a good backup in place of your full site and database. You can ask your host for backup functionality or you can consider using a service like Jetpack. If something goes wrong, you will be able to restore it.
If the issue persists, please share a copy of your site’s System Status to understand your site setup. You can find it via WooCommerce → Status → Get system report → Copy for support. Once you’ve done that, you can paste the text in https://gist.github.com. After that, you can paste the Gist link here in your reply.
I hope that helps! Let us know how it goes.
Thanks!