What do you mean, permanent?

 

Copic markers are permanent on most surfaces means that it won't easily come out of things that were not paper. On nonporous surfaces like metal or acrylic, the ink never sinks into the material. This means that if your ink is too thick it will remain slightly gummy. Try to avoid using to much ink.

Dry ink can still be scratched off nonporous materials with something sharp, so seal your work to add protection if the object will be touched or rubbed frequently.

On fabric, quilters have had good results with using markers on wallhangings. Copic does not recommend wearables, given that the markers are alcohol-based dye. A drink spilled on the ink might interact with your pattern, and some dark colors may bleed when washed. Experiment with Copics on fabric on your own to see what works for you.

The dye will face at about the same rate as other fabrics, so treat it with the same care you would other fiber arts - keep out of harsh lights, etc. Otherwise, test each fabric. Copics are permanent and have been used on leather and cotton with good success. just be careful.

Multiliners are permanent on fabrics if you heat-set them. I myself have also used Copics on fabric shirts and book bags. I heat set everything before washing.