Is there a way to add the buyer to the title to show they own the property free and clear if the owner is going to carry the loan?

Not sure what you mean "owner is going to carry the loan".

If you mean the owner owns this property free and clear of any senior liens and is going to be the bank then YES the buyer would want the attorney to transfer title to from the seller to the buyer. The seller is still the bank now so if the buyer does not pay they can foreclose on the note and get the property back.

If you mean the seller still holds a senior mortgage then transfer of title will really not mean much. The seller couldn't create anymore junior liens which is good as they would not have title anymore.For the buyer though it could be a bad deal as you have no guarantee the seller taking the buyers payments is paying the mortgage. Then the buyer who owns title gets a nice foreclosure notice in the mail with the sellers name on it and all the buyers money is gone.

Owner will carry can mean many different things. With alternative financing you have to know what you are doing to protect all parties involved.

no legal advice

Depends on the laws in your state. In fl yes you can. But then propeses the question why would the owner do that????????