Hello, @vitorlmc,
When I check your site I found that there is a CSS code that hides the title from the product page as you can see in the image: https://postimg.cc/5H9QX8N1
Now, In order to solve your issue simply go to the Dashboard,>> XStore >> Theme Options >> Theme custom CSS >> Global, and then paste the below code at the bottom of the CSS box.
.single-product .product_title{display:block !important;}
Then save settings and check back to your site after clearing the browser cache. The result will appear as you see in the image: https://postimg.cc/5X42gbcS
Regards 8Themes Team.