Open the account menu
Click the round button with your initial in the top right corner, next to the notification bell. At the top of the menu you see the name of the account you're in right now, with its email address and plan.
Pick an account from the list
Further down the menu there's a Switch account section. It appears when you have at least two accounts with the same verified email address. The active account has a green check mark, and next to each one you see its role: Your account or Team.
Work in the account you picked
After switching, you see the clients, galleries and settings of the account you picked. Everything you do is recorded in that account's activity log, under your name.