Look up how the FTB defines "doing business" in California and you'll likely see that it is pretty broad. 

Below is a broad summary of probable expenses, along with some aspects to take into account:To lay a strong foundation of knowledge, set aside money for real estate education, books, seminars, and courses.

@Mike McCarthy very good, but yeah I was thinking a little more broadly.  

Same - Does anyone Know of Spectrum Global Financing or Sure Lend LLC?

@Michael Baum You're right, my statement was probably too broad.

Depending on your goals for the property and how much underwriting you want to be subjected to - your options are broadly as follows. 1) If the property is habitable and just needs some updates and minor repairs and you would like to keep it as a rental - conforming loans will be the cheapest rate and fees, require full underwriting on you, and your income will be considered to buy the property - think DTI ratio. 2) If the property is not habitable that leaves you with something like a hard money loan or private loan - which are normally short term debt.

Not usually a good way to start off a new business venture or to pitch a loan officer, so take that into account and think about narrowing down and coming up with a real plan so you know what you’re looking for and how you will execute it (broadly).If you ever have questions on Ag RE/investing, financing, etc feel free to DM me!

If you're asking what a REI (real estate investor) does, that can be a pretty broad answer, anything from tax deeds/liens to rental properties to raw land with natural resources.

I don't foresee branching out beyond multifamily investing but you never know, might as well go with a name broad enough to have the larger support structure as you suggest. 

Ultimately, people either end up on one side of the spectrum or the other.