During its introduction phase, you must opt-in to use 3D features.
Restricting access
Before you enable it, consider its exposure. All of your workspaces (and its users) will be able to convert charts to 3D, once enabled.
You may disable 3D for some or all of your users by disabling the feature when embedding the designer. This can be done before you enable 3D for your account.
Enabling 3D for your company
To enable 3D, head over to your Company Settings, in the New Features tab. Click here to go to New Features.
Locate the 3D Charts option, and choose Enabled.
Converting a chart to 3D
Charts by default continue to be rendered in 2D, and they need to be turned into a 3D, a process that only takes a few minutes of work once the basics are understood.
To learn how, please read the article: Converting a 2D chart to 3D.
Configuring 3D
It is possible to configure certain aspects of 3D rendering. Read more at the docs.