The audit trail acts as proof that the signature process was done properly. It shows who signed the document, when they did it, and how they verified their identity.
The law does not distinguish between a typed contract and one written by hand. What matters is whether the contract contains the essential elements that make it enforceable.
For a contract or legal document to be valid, check for consent, competent parties, consideration, lawful purpose, clear terms, signatures, dates, and witnesses.