If you wish to move to Sweden to live with a close relative who is already a Swedish resident, you must have a residence permit of your own. This applies for instance if you are married or cohabiting or intend to marry or cohabit with someone who is permanently residing in Sweden. It also applies to unmarried children under the age of 18.
Armenian citizens can apply for residence permit at the Embassy of Sweden in Moscow. The Embassy of Sweden in Yerevan does not receive or process applications for residence permit.