Does one need to have the original signature on the contract or change an order or even release paper, etc. to have a legally binding contract? The answer is that it is not really needed and here’s why.
Your agreement is valid when it’s an agreement between the other party and you. The written document is only a manifestation of that agreement. So, there are other ways both parties set terms for an agreement. It doesn't have to be a signature. If you have a sign, you can worry about originality. How does one know that it's enforceable? So, understand that it's rare, very rare that there are cases where you'd run into a forged document. It's so rare that it should be last on your list of concerns. But still, what would you want to do to increase the likelihood of protecting yourself from not having an original signature. Number one and the most important advice would be to make sure your email correspondence to and from the parties that are concerned are inked in the transmission of the contract or request for contract and signature. For e.g., if you want a signed contract, you could send a request with a copy of the contract to the other party and have them sign it and send it back to you so you not only have the document as evidence but besides, you also have correspondence from the email that they have signed it.
But these should be the least of anyone's concern as it's all taken care of by professional Construction Law Firms.