It does not take much to work on your guitar. You can easily purchase a special workstation that supports and holds your guitar while you work on it (as pictured). But generally it is easy to find everything you need around your house already.
At a minimum, you need a surface that you can lay the guitar on that will not scratch the surface. If you are working on the electronics or something on/in the back of the guitar this could easily be a towel on a table or hard surface. When you are working on the front of your guitar and you need to lay it on the back, you can also use a towel and put a soft shoe (like a tennis shoe) to support the neck so there is minimal or no weight on the headstock.
You can work on your guitar anywhere and on pretty much any surface. It is just prudent to try and find or make an area where you are able to minimize the possibility of damage to your guitar. It is also helpful to find an area that allows you quick access and areas to place your tools.