You can change your main email address both from your web or mobile application. It's a three step process starting with accessing your profile, changing the email and confirming the new email to complete the process.
Web application
Go to My Profile
Type in the new email
Go to your inbox and confirm the change email
It can take up to 5 minutes to receive the confirmation email
Mobile application
Click on the menu on your top left
Click on My Profile
Type in the new email
Go to your inbox and confirm the change email
It can take up to 5 minutes to receive the confirmation email