Birth control pills
The pill is a hormonal birth control method. The hormones prevent ovulation – when your ovaries release an egg – and thicken cervical mucus. These two actions make the pill very effective at preventing pregnancy.
How it's used
Depending on the brand of pill you're taking, and the combination of hormones it contains, your instructions will vary a bit. In many cases you'll take one pill at the same time every day, or within the same two-hour window of time every day. Each pill contains 24 hours' worth of hormones. If you don't take the pill at the same time every day, it won't work as well!
Unless you're taking the mini pill, each pill pack will contain three weeks of pills containing hormones and one week of "placebo" pills that have nothing in them. The week you take those pills would be the week you get your period, and even though there's nothing in them, it's helpful to still take those placebo pills so you stay in the habit of taking a pill every day.
How well does it work?
If you take your pill at the same time every day, it is around 99% effective at preventing pregnancy. Because people sometimes forget to take their pill or take it late/early, the effectiveness on average is around 92%.
How do I get it?
You'll need a prescription from a medical provider. You'll also have to make an appointment first, when the doctor will discuss the different options and help you decide which one is best for you.