Find a fox in a taiga, snowy taiga, old growth taiga, or grove biome
Bring sweet berries or glow berries
Sneak up slowly so the fox does not run away
Feed two foxes sweet berries or glow berries to breed them
Wait for the baby fox
Use a lead to keep the baby fox close
Raise the baby fox until it grows up
The baby fox will trust you and stay near you