There are two ways to access your profile and update your personal information depending on which device you're using.
On the website
After logging in, click on the downward arrow next to your username in the top left-hand corner of your screen. Click "Settings," then "Manage Account" to change your personal details.
In the app
Tap on your profile icon in the bottom right-hand corner of your screen, then tap the gear-shaped icon in the top right-hand corner of your screen to access your settings. You'll then be able to change your personal details under "Account". Then tap "Save" in the top left-hand corner of your screen.