question on stamping [closed]

There's a lot of confusion in your post. I'll try to answer, but if you could provide more information, we could help you better.

First, if you were born in the United States, and you didn't renounce your US citizenship, you are a US citizen (if you were the child of a foreign diplomat serving in the US at the time, you might not be a US citizen by birth, but we'll set that aside because it's complicated).

US citizens do not need, and will not receive, a visa to enter the United States. US citizens must have and use a valid US passport to enter and exit the US. You'll need to show a valid US passport to the airline representatives (to demonstrate that you'll be allowed into the US) and to the immigration officer when you arrive. You do not need to obtain any kind of stamp. If you don't have a valid US passport, you should get one before you travel.

The only point where a stamp is involved for a US citizen is after you've presented the immigration officer your passport. He or she will examine the passport to ensure that it is valid and belongs to you and may then stamp it just to show that you entered the United States. It is also possible that you won't receive such a stamp (you likely won't get a stamp if you use one of the automated passport kiosks). It doesn't matter; no stamp at the border is required for US citizens.

Note also that this all applies to entering the entire United States, not just the one state of California. Once you are already in the United States, no passports or stamps or visas are required or involved specifically to enter California or travel between any states (note that some sort of ID is required to fly within the US, and a passport is one of the options).