Adjectives in Russian language have two forms: long form and short form.
Long version of adjective ends on -ЫЙ, -АЯ and -ОЕ. For plural, ending is -ЫЕ. For example, КРАСИВЫЙ, КРАСИВАЯ, КРАСИВОЕ and КРАСИВЫЕ. Long form of adjective changes according to gender, number and case. They can be used in a sentence as attribute or a predicate.
Short version of adjective changes only with gender and number. For example, КРАСИВ, КРАСИВА, КРАСИВО and КРАСИВЫ. They can only be used in a sentence as predicate.