xcode13.3.1. Where can I find interface builder? I want to add a text column.

In your screenshot, you are looking at interface builder!

Perhaps you mean that you want to see the Document Outline, to the left of your View Controller?
If so, click the icon at the bottom-left...

...or perhaps you mean that you want to see the Object Library, in which case click the "+" icon (at the top-right).