Hi Mitko,
If you are referring to the marked section in the given screenshot as content, it is coming from the Short Description.
To get the Description Tab you need to add the content as shown in the given screenshot in the previous comment. If that is already added, there might be some different reasons behind your reason. I would like to suggest troubleshooting the following common issue to help us to recognize the reason.
1.Theme Related Issue
2.Plugin Conflict
3.Theme Update related issue
4.CSS/JS Customization
5.Disabling Cache
6.Disabling CDN
If you discover that an issue is coming from a custom code or 3rd party plugin, kindly consult with a developer or contact the plugin author. Please note that we do not provide support for custom codes and 3rd party plugins.
If none of the above help, please copy your live site to a staging server so we could troubleshoot freely without breaking your live site.
And give us access to the secure note including:
– WordPress Site URL & Login URL
– WordPress Admin username/password
To create a secure note, click the key icon underneath any of your posts.
Thanks