Final answer:
The clause in question is an entire agreement clause which requires that modifications to the employment contract be in writing and signed by both parties to be valid.
Step-by-step explanation:
The clause from the employment contract, "Any modification to this Agreement must be in writing and signed by the parties or it shall have no effect and shall be void," is known as an entire agreement clause. This means that any modifications, amendments, or changes to the employment contract must be made in writing and signed by both the employee and employer; verbal agreements or promises are not recognized.
Such clauses reaffirm that the written contract embodies all terms of the agreement between the parties and prevent disputes over alleged oral agreements not captured within the written contract. Courts frequently enforce these clauses as they contribute to the clarity and stability of contractual relationships.