Hello! "Them" is an object pronoun. It replaces nouns that are the objects of sentences. E.g. Jennifer and Clara become annoyed when Angus tries to do their work for them (In this sentence "them" replaces Jennifer and Clara) "Their" is (possessive) belonging to, from, of, or relating to, them. E.g. "Their friends are coming" (Whose friends? - Their friends)

I notice you are from Russia. And I see why there is confusion. Пробую объяснять На русском, слово "их" это "them" и также "they" но на английском у нас 2 другие слова. them - их (винительный падеж слова "они") например: I see them Я вижу их their - их (притяжательная форма слова "они") например: Whose book is this? It's their book. Чья это книга? это их книга.

Tell them to get their coats. It is raining. them - third person, plural pronoun, = those people they did this. Tell them to do this. their - third person, plural possessive pronoun, their coats = the coats owned by them. Them and their are sometimes used for singular (1) person if the gender is unknown. That is, instead of he or she.

“Their” is the possessive of “them” it means his, hers or it’s but more than 1. “I was sad when their plane crashed. Their music was really good. Too bad nobody remembers their name.”