Coil splitting shuts down one of the coils of a humbucker pickup to create a single-coil tone.
To be able to coil-split, you’ll need pickups with 4-conductor wiring (colored red, green, white, and black) and a bare earth wire.
Pickups come with schematics to coil-split a humbucker. If yours doesn’t, you can find them online.
The process is simple: coil tap the finishes of each coil so that instead of four connections, you only have two. This can be done with a bit of solder and shouldn’t take long.