Your workspace and timings will depend on where you work. Many graphic designers choose to freelance. They choose how many projects they want and what kind of work they want to do. As a freelance graphic designer, you could work from home or even a cafe. If you're working for an organisation, you will work out of their office and follow their work timings. Sometimes, you may even have to extend your working hours to meet a deadline.
An essential requirement of your job is the ability to spend long hours in front of a computer. You might use a high-end computer or graphics tablet and work at a desk like most office employees. Here's the fun part though; you get to create brilliant designs all day long and watch your imagination come to life!