Final answer:
The phrase 'put your John Hancock here' is an allusion to the famous and prominent signature of John Hancock on the Declaration of Independence, which has come to represent the act of signing one's name.
Step-by-step explanation:
The allusion in the sentence 'put your John Hancock here on the form, please' means a reference to a famous signature. The term 'John Hancock' has become synonymous with one's signature because John Hancock famously signed the Declaration of Independence with a large and prominent autograph, leading to his name representing the act of signing. The allusion is both a request for a signature and a mention of a historical figure, but most directly, it refers to the act of signing one's name in a notable way, much like how Hancock did on one of the United States' foundational documents.