Every eligible citizen (Swiss national and >18 years of age, no registration needed) gets a ballot in the mail here, usually a few weeks before the election/vote. There also is a booklet with the actual bills voted on, pro and contra arguments, outcomes of congressional votes on it and a neutral explanation. You can fill it out and send it back in the mail free of charge (in most places, some you still need to get a stamp) up until the week before the vote. The actual voting day is always a Sunday and if you want to you can drop by the polling places (there are enough of those, at least I never had to wait longer than a few min) to hand in your ballot personally.