In my experience, schools do send them out by email, the one designated on your app when you submitted it. Usually they will give you a link, and username/password (a lot of times it's your AMCAS ID number), you log in, and the prompts will be there. Most of the time the essays are similar from year to year but they could change it, and that's all up to the school. Depending on which schools you applied to, they may start sending you secondaries before verification...just don't forget about the $$$
Ideally 1-2 days = great but I think a week or two should be fine too (check me on that). Usually they give you a hard deadline (i.e. 4 weeks after they email you), and if you dont get a deadline you want to submit AT MOST before that month is over, anyhow.