thingiverse
This is a standard key template. To make it fit into your own to door, you can import the model into e.g. Onshape and a picture of your key. Then you can draw the outline of the key and remove the material afterwards.
You can also use a file after you have printed the template key.
I printed it with 0.1 mm layer high and it worked as a functional key in my door.
Here is a video that goes more in depth:
https://www.youtube.com/watch?v=FDcyqHvAt3Y
Direct link to the original creator's page
Click the "View on thingiverse" button above to visit the original model page on thingiverse. You can download the STL file directly from the creator's page for free.
This STL file is compatible with most FDM 3D printers (Creality Ender 3, Prusa MK3S+, Bambu Lab, etc.) and resin printers (Elegoo, Anycubic). Check the original page for recommended print settings and materials.
Yes, this model is available as a free download on thingiverse. Some creators accept tips or donations.
Most STL files can be modified using free software like Blender, TinkerCAD, or Meshmixer. Check the license on the original thingiverse page to see if modifications are permitted by the creator.