Hi, when i switched my website to Storefront theme, problem solved!. You can see it in the attached image. https://snipboard.io/Uzyn4C.jpg
I tried it with a plugin, I also tried it as in the woocommerce documents, but the problem did not improve. I think the problem is with the theme.
*You can connect to the site and test it yourself.
https://docs.woocommerce.com/document/tutorial-customising-checkout-fields-using-actions-and-filters/
