Places help shape the things that happen there.
A classroom doesn’t look like an office doesn’t look like a church. All classrooms (etc.) don’t look alike either. They aim to shape different things. Some work better than others.
Some people can write anywhere, anytime. When you’re stalled or stuck or feeling balky, though, having place on your side can be very helpful. Classrooms, offices, and churches help people focus on whatever they’ve come to do: learn, teach, work, worship, whatever. Your writing place can do likewise.
It doesn’t have to be a separate room with a door that closes, though if you live with other people this might help.
It doesn’t have to be a place you use only for writing either. Plenty of good writing happens at kitchen tables. I write in the chair where I also sit to edit or read. When I sit down to write, I light a candle or two. If a candle is burning, it’s writing time.
Particular objects and rituals can help turn ordinary time into writing time, an ordinary place into a writing place. Experiment. Pay attention to all your senses. Candles, incense, music, a favorite glass or cup or mug, a special photo — any or all can help create the place where writing happens.
Actually writing in that place makes the place more conducive to writing. That might be the most important factor of all. So don’t obsess too much about making the place perfect. (Perfectionista is always lurking in the background, waiting for a way to get into your head.) If writing doesn’t happen immediately in your writing place — just write. Write anything. Write the same sentence over and over again. Do it for 10 minutes. Then do it again tomorrow.