The 11 of September Sweden holds general elections.
The Swedish Embassy will offer to opportunity to vote on site during the end of August. More details regarding exact timeslots are to be determined.
If you need to register to vote read more here: Ny adress/röstlängd för utvandrad, Anmälan (SKV 7842) | Skatteverket
If you are registered to vote and live abroad voting material will be sent to your registered address. You can also order voting material here: www.valmyndigheten.se. It is also possible to collect voting material to vote by mail at the Embassy starting 28 of July. Votes by letter needs to have arrived in Sweden by 10 of September to count.
Read more about voting abroad here: Rösta från utlandet - Valmyndigheten