Kentico - Missing 'Form Controls' tab

I'm using Kentico 13 .NET Core and trying to build a custom form control. However, as mentioned in following article, I cannot see the 'Form Controls' tab to register my custom control. What am I missing?

https://docs.xperience.io/custom-development/extending-the-administration-interface/developing-form-controls/example-developing-custom-form-controls

Form controls are under Development > Administration Interface. You can add and update them from there.