Stylistically, Fino and Manzanilla are the same but there are dramatic differences in their pedigree and flavour profiles.
Fino is a light, dry, pale fortified wine from Spain made from the Palomino grape. It is aged under a veil of yeast, known as a flor, and is perfect served chilled as an aperitif.
Manzanilla is made in exactly the same way as a fino, only it must come from Sanlúcar de Barrameda in Spain. This is a region that is closer to the coast and hence has a more maratime influence giving Manzanilla it's trademark salty character.