probate

What is the name of your state?
CaliforniaWhat is the name of your state? California

I'm trying to find a few answers about probate. If someone dies leaving no will does it always go into probate? And who would be the person that would set the probate into action?

It depends on your state of residence, but generally if you die with no will your estate will go to probate and a judge will decide where your assets go.

Where did the decedent live? I assume California.

Was the decedent married? If so, was there any separate property?

If the decedent was not married, let's divide the assets you are concerned with into two lists:

the first contains assets title to which can be cleared by contract terms, such as by a surviving joint tenant, a pay on death beneficiary, or a life insurance beneficiary.

the second contains assets in the decedent's name alone.

If the assets in the second list are worth over 100k, then it looks like one of the heirs at law will need to open a probate.