THE SHORT ANSWER
All three usually combine espresso with heated, textured milk. A latte is generally milkier, a cappuccino foamier, and a flat white smaller with fine microfoam and a more coffee-forward balance. Exact sizes and definitions vary by café and country.
The cup tells part of the story
There is no worldwide café police issuing identical cups. Ask how many shots and what size the drink contains. A large flat white on one menu may have more milk than a small latte at the next café. Names help, but the local recipe settles the comparison.
Texture changes the experience
Steamed milk can feel glossy and fluid or airy and pillowy. Those textures affect how coffee and milk arrive together. Cappuccino tends toward a more noticeable foam layer; a flat white generally uses a thinner layer of finely textured milk. Your preferred milk or plant drink can change the result too.
A useful ordering sentence
Try: I would like a small, coffee-forward milk drink with fine foam; what is closest on your menu? That gets you farther than arguing about a drink you had in another city. For home brewing, use one familiar espresso recipe and compare different milk amounts before spending the afternoon trying to draw a perfect fern.
Change one thing, taste, and keep a short note. A recipe becomes useful when you can repeat the cup you enjoy.
Try it for yourself
Sources & further reading
Source links support the factual context. Our home recipes and tasting suggestions are identified as starting points.