This is the 534th most frequent Ukrainian word.
їхні
"Their" (possessive pronoun).
The word 'їхні' is used as a possessive pronoun, denoting that friends belong to or are associated with 'they'.
Їхні друзі завжди приходять на допомогу.
Their friends always come to help.
Here, 'їхні' again serves as a possessive pronoun, showing that the documents belong to 'them' or the group referred to.
Вони забули їхні документи на столі.
They forgot their documents on the table.
In this sentence, 'їхні' works as a possessive pronoun, attributing successes to the people referred to as 'them'.