If you are in a services field, then you should have a space where you have a collection of your work. When I say services, the examples that come to mind at the top are: contractors, organizers, event planners, photographers, just to name a few. Keeping an collection of your work is a nice way to keep track of your achievements. Its good for potential clients to see too.
Your portfolio can contain client testimonials, published works, awards, certifications, and of course photos! Photos, photos, photos! Some people have a folder on their tablets or laptops. Others actually have a “physical” portfolio. You can get special folders and holders for that. And of course if you have a website, you should have much of these things on there too.