https://ibb.co/F6zFTjT

You are... running Forge. What did you expect to happen?

This is not a Forge mod, it's a Fabric mod. Putting Fabric API in your mods folder doesn't mean you're using Fabric - you need to actually use the Fabric mod loader, as in instead of Forge. Fabric and Forge are both mod loaders, you can only use one or the other.

Head over here to set up Fabric: https://fabricmc.net/use/