There are two fundamentally different methods for resending a claim. These two methods are resubmitting the claim and filing a corrected claim. How you resend a claim to the insurance company usually depends on whether they rejected or denied the claim. For information on rejections versus denials, please see: Claim Rejections and Claim Denials.
Resubmitting a claim
When you resubmit a claim, you are creating a new claim and sending it to the payer. The payer receives the claim and treats it as a new claim.
Filing a Corrected Claim
When you file a corrected claim, you are not creating a new submission. You are taking a claim that you previously sent and sending it to them again in such a way that the payer knows that this claim they are receiving has already been adjudicated by them and they should treat this new claim as a correction of a claim already in their adjudication department.
The problem arises when you resubmit a claim that was denied (as opposed to rejected). Because the original submission was denied, it is recorded at the insurance company as already having been adjudicated. When resubmitting, you are telling the insurance company "Here is a new claim". The insurance company receives it and says "this claim is a duplicate of a claim we have already adjudicated". This will result in a duplicate claim rejection (not denial) of your resubmission.