Any one can use bitcoin. It depends upon the person's interest in this technology. One can learn it from Google articles and by doing his own research over it, do hard work and apply it. It can also be operated through mobile phones, if one cannot afford computer as maximum number of the people are connected to internet through smartphones.
Yeah bit coin is an globally accepted crypto currency, anyone can use it anywhere all around the world. Ordinary citizens who have a lot of interest in modern digital technology they can make use of bit coins in international markets for sale/purchase or trading their bit coins to make profits.