question

You can get a signature from the VerifySignatureRequest object the Clover device sends after a customer signs using the onVerifySignatureRequest() call. After you retrieve the signatures, you can store them on your own servers.

public override void OnVerifySignatureRequest(VerifySignatureRequest request)
{
  base.OnVerifySignatureRequest(request);
  //Signature object
  Signature2 signatureObject = request.Signature;
}

Note that this method is only valid for signatures taken on the device screen (not paper receipts).