I received a summons from the Superior Court (civil). I would like to respond to this summons, however, I have been unable to locate the proper "answer" form online. A credit card company is suing me for $1811.00. I live in Riverside, CA, county.

I have been unable to locate any old bills from the company. I do not recall doing business with this credit card company.

That amount sounds like a small claims case?

If so, you probably just need to show up on the court date, and demand that they
Produce proof of the debt.

If they can, you could offer some type of defense, or set up a payment plan.

If they can't, you will win and they will loose.

If it is in fact, just asking you for an answer, all you really have to do is type or write a response to the effect of I deny this debt, and will appear for a hearing to defend myself.
If it states that you have "x" number of days to respond, I would hand deliver it to the court myself and get some kind of receipt for it.

Good Luck!