While not an exact replica, you can find "vlog" or "split-screen" templates on Canva that mimic the multi-panel aesthetic.
To remake manually:
The easiest way to get the look without building a 3D environment from scratch is to use pre-made templates: CapCut iCarly Theme Template icarly intro template free
The iCarly intro is famous for its "window-in-window" look. To mimic this in a project: While not an exact replica, you can find
Remove the watermark if you buy CapCut Pro, or crop it out. Save to your phone and upload to TikTok with the hashtag #iCarlyEdit. While not an exact replica