Sometimes 007 has to use aliases, another identity during his missions.
Sometimes they are just made up identities and sometimes he’s impersonating someone else in the film
This is a list of the two types.
Aliases
David Somerset (with wife Caroline) in “From Russia with Love”
Mr Fisher in “You only live twice”
Taro Torodoki in “You only live twice” (from Fleming’s novel, not actually stated in the film although same character)
Mr Jones in “Diamonds are Forever”
Robert Sterling (with wife) in “The Spy who loved me”
Charles Morton (of Leeds) in “Octopussy”
St. John Smyth in “A view to a Kill”
James Stock in “A view to a Kill”
Jerzy Bondov in “The Living Daylights” (given by villain Koskov)
Arlington Beech in “Casino Royale”
R. Sterling in “Quantum of Solace“
Impersonations
Sir Hilary Bray in “On her Majesty’s Secret Service”
Peter Franks in “Diamonds are Forever”
Klaus Hergesheimer in “Diamonds are Forever”
Burt Saxby in “Diamonds are Forever”
Francisco Scaramanga in “The Man with the Golden Gun”
Colonel Toro in “Octopussy”
Dr Mikhail Arkov in “The World is not enough”
Van Bierk in “Die Another Day“
007 Under the Mango Tree 
jculwestside
August 8, 2013
Definitely going to be using some of these aliases next time I have to go off the grid
JAMES
July 7, 2014
I once told a telemarketer my name was David Somerset and I used Mr. Fisher as a pseudonym for a short story I wrote a year ago.