The vast majority of countries around the world offer some sort of student visa option. A student visa is a visa that allows you to enter a country in the name of academic study. You do not need a student visa for any sort of recreational education (guitar lessons, for instance), only for education that will earn credits towards a degree.
Generally, student visas are intended for post secondary education. This means colleges, universities. Many exchange students in high school or earlier find themselves needing to obtain a different type of visa, typically a visa allowing for temporary residence.
You may have already obtained a visitor visa, perhaps to tour a university you were considering attending, but before you begin studying, you absolutely need to attain a study visa. Most countries will not allow you to attend an institute of higher learning without one. It varies from country to country, some places are more flexible than others, but the key factor is generally going to be whether or not you are earning credits towards an academic degree.
You may have to go through an interview process in order to attain a student visa. This will follow filling out your visa application, providing all of the paperwork (you’ll need to prove that you’ve been accepted to a given school, for instance), and sending in a recent photo with the form.
New students will generally receive their visa within 120 days of their course, depending on a number of factors, and again, it varies from country to country, this is just a rough average. Continuing students will generally have to renew their visas from time to time depending on the country’s study visa policies. Application fees can range up to $150 and more, but this can generally be covered by student loans and scholarships.