You’ll find I use window light quite a lot to take posed and candid portraits of my friends and family. I find window light is easier to manage for me than flash. And it’s very easy to find. I am sure you have a favorite spot in your house that gets nice light during certain times of the day without being too harsh, or that is filtered by a white gauzy curtain.
I was with my father in a coffee shop when I noticed the window at my left shoulder and the window at his left should were both wrapping a very even, natural light around him and made his navy cap and reddish sweatshirt pop. So I took several shots (see two more below), but really liked the natural easy expression here as he watched my sister with my niece interacting. For me, the soft shadows make the setting feel very real and comfortable.
When using window light, you may find you need to increase your ISO to 400 or 800, depending on just how bright the light is. You can shoot in program (not green box mode which may make your ISO too high for a pleasing portrait), or in aperture priority mode like I selected here. I shot wide open at f/2.8, 400 ISO, and my shutter speed then defaulted to an easy to hand-hold 125th sec.
Here are a few posts that also discuss window light: