The team post offers a nice summary:
You take a lot of photos, but you don’t always have time to organize and share them. Picking out the best photos and making an album – especially after a trip – is time consuming. More often than not, you never share those photos and they end up sitting on your phone or computer.
Starting today, Google Photos will suggest a new album for you after an event or trip, curated with just your best shots. It’ll add maps to show how far you traveled and location pins to remember where you went.
You can customize it, add captions, and turn on collaboration to let others add their photos. Before you know it, you’ll have a beautiful album ready to share.
You should see the change automatically as long as you’re on the latest version of the app.