Discovered after 15+ days of talking to Sable daily, she gives you patterns that add a customization window on furniture. This is a separate option from the Custom Patterns you create. :
I love Animal Crossing, and I love Celeste. Felt appropriate to combine the two for my first custom furniture piece! : r/celestegame
Furniture customization - Animal Crossing Wiki - Nookipedia
Animal Crossing New Horizons How To Customize Furniture!!! - YouTube
Animal Crossing: How to Customize Ready-Made Furniture
Animal Crossing: New Horizons: Custom Designs - How To Customize Furniture And Import Designs | Nintendo Life
Nook's Cranny - Animal Crossing: New Horizons Guide - IGN
Animal Crossing: New Horizons: Custom Designs - How To Customize Furniture And Import Designs | Nintendo Life
Custom Designs - Animal Crossing: New Horizons Guide - IGN
Pin on Animal Crossing ❤
List of Items Customizable with Custom Designs | ACNH - Animal Crossing: New Horizons (Switch)|Game8
Using the QR code and custom design maker in Animal Crossing: New Horizons (Switch) - Polygon