Everyone writes in different places. Some of us are lucky enough to have a desk in a spare room at home where we can keep our computer and the books and pictures we are currently using as reference. Some make do with the kitchen table when it is not needed for family meals. JK Rowling wrote much of Harry Potter in a coffee shop. Roald Dahl had a shed in his garden in which he created his children's fantasy.
Today I was on a train to Edinburgh and I had my laptop with me and found it easy to write in the time that would otherwise have been spent glancing through the Metro (free newspaper) or staring out of the window.
For some people writing is a state of mind that you can do anywhere.
But I guess that everyone interested in writing always carries a notebook around with them for you never know when you will; get a brilliant idea that you will otherwise forget by the time you get home!
The bottom line is it doesn't matter where you do it - if you want to be a writer don't procrastinate - just do it!