If a candidate chooses to sign by simply typing their name as shown
(as an example) in the first and second photos, they'd obviously have
to stick to the same name and font when signing the contract and
non-disclosure agreement.
This assertion is incorrect.
But what repercussions would it have in future? If the candidate has
to sign any more company documents much later (signing physically with
a pen on paper or even signing electronically), would it have to match
with the signatures that were first made in the offer letter?
No.
Or would commonsense be accepted, that the signature is basically the
candidate's acceptance of the terms of the agreement, and that the
signature can vary?
Yes.
A signature is ritualized way of showing legal agreement.
The content of the signature does not impact its legal validity.
For example, it used to be commonplace for illiterate people to sign contracts, wills, and other documents prepared by someone else and read to them with an "X".
So long as a signature is made by the person who is supposed to be signing it with an intent to legally agree to what they are signing, it is a valid signature.
When a signature is obtained in a manner that does not reflect the intent of the person signing it to legally agree to what they are actually signing, that is a special category of fraud called "fraud in the factum".
For example, substituting a deed to a house from a receipt for a package delivery at the last moment when the person signing it doesn't notice the switch, is "fraud in the factum".
A court's conclusion that there has been "fraud in the factum" has the legal effect of causing the document signed to be treated as if it was never signed at all. In contrast, different legal consequences are present when someone signs a document, knowing what they are signing, for reasons that rely on false statements that have been made to them, which is called "fraud in the inducement."
If someone tries to enforce an agreement that purports to be signed, and the person who allegedly signed it claims that the signature was forged by a third-party, inconsistency between the signature and other times that the person who allegedly signed something did so is evidence that the signature is a forgery.
But it is not conclusive evidence. People's signatures change over time for a variety of reasons, sometimes dramatically in a short period of time, for example, in the case of a stroke or a hand injury.
When signatures differ over time and there are allegations of forgery, then it is a question of proof for a finder of fact (i.e. a judge or jury) to decide if the alleged forgery is really a forgery.
Many businesses that routinely accept small dollar value personal checks, for example, also take a thumb-print of the person signing the check in order to make it cheap and easy to litigate the question of whether a signature on a check is forged, and to discourage litigants from falsely claiming that a check was forged in the first place. This practice was established because lying and claiming that a check was forged used to be a tactic that was used on a recurring basis in civil cases and in criminal bad check passing prosecutions to escape liability.