If you're looking for a way to say "Tatum" in Spanish, you would simply use the name as it is: Tatum.
However, if you're trying to convey the meaning of the name, which is usually associated with "sweetness" or "joy," you could use words like:
* Dulce (sweet)
* Alegría (joy)
* Felicidad (happiness)
It really depends on the context and what you're trying to communicate.