"My sister lives in Russia."
Translation:Моя сестра живёт в России.
The possessive modifier (כינוי השייכות) must agree with the noun it modifies in gender, number and case (e.g. genitive, accusative, etc.). See for instance here: http://www.study-languages-online.com/russian-possessive-pronouns.html
@SinanZarif1 - That's the third person singular conjugation of the verb zhit'. When it comes to verb conjugations an easy resource to use is Wiktionary.org You can look up a lot of foreign words through the English page and see the conjugations and English explanations (though the Russian language page for the word will usually have more information).