If getting 3 bleeps how do I correct ram

I assume from the site you came here from you believe your RAM to be faulty.

You don't correct failing RAM, you replace it; some RAM can be replaced depending on the model of your Mac.

27" iMac's RAM can be replaced by the user, not so with the 21.5" models. At least not easily.

There are guides on the internet on replacing 21.5" RAM, but the process is not simple or user friendly.

How old is your iMac? It may be time to retire it .

Good advice above. I also offer the following thoughts. RAM cards, if added or replaced, should be used in pairs. It is very important to install RAM that a Mac can work with. They are particular. Many of us here recommend that RAM be purchased from crucial.com or mac sales.com. They support their products and can tell you which RAM your Mac can accept. They are also a lot cheaper than the Apple web site.