We'd have to know more about situation to answer your question. Did you plan to permanently move to California? Did you take any steps to become a CA resident such as getting a driver's license, registering to vote or signing a lease for an apartment? Did you work in CA?
If you did not try to establish California residency, file a non-resident California return and report any income you earned while you were in CA, otherwise file a part-year CA return.
When I moved to California, I thought it might be permanent, but it ended up only lasting a few months because of a new opportunity for 2021.
I did register to vote, but that is the only thing I did to establish residency. I did not sign a lease, and I am self-employed with a permanent address in Florida.
Should I then file a non-resident California return?