Buffer solution resists change in pH when small anounts acid/alkali added. The pH of the solution stays roughly the same (or any variation is negligible).

Acid buffer... pH less than 7. Made up from a weak acid and one of its salts, typically sodium salt. eg ethanoic acid and sodium ethanoate.

Alkaline buffer ... pH greater than 7. Made up from a weak alkai and one of its salts, eg ammonia and ammonium chloride is a common example.