The first paragraph of the story uses several figures of speech. The paragraph runs:

Marley was dead: to begin with. There is no doubt whatever about that. The register of his burial was signed by the clergyman, the clerk, the undertaker, and the chief mourner. Scrooge signed it: and Scrooge’s name was good upon ’Change, for anything he chose to put his hand to. Old Marley was as dead as a door-nail.

The first and most obvious figure we encounter here is amplification. A single piece of information—the death of Marley—is delivered to us in several sentences, each minor variations upon a single fact. The purpose of this figure is to emphasize the significance of his death and its importance to the people around Scrooge. 

The extended description of the certification and confirmation of Marley's death is an example of the rhetorical figure of enumeration (Latin: enumeratio), which explains a complex point or concept by breaking it down into simple steps or details and listing them. 

Finally, Dickens uses a simile in the phrase "dead as a door-nail," a phrase that compares a dead person to an inanimate object that never lived to emphasize absence of life.