You can change your email address from the account settings page on the Dropbox website.
Once you change your email address, you will use it to log in to Dropbox and all Dropbox-related emails will be sent to the new address.
If you’re a member of a Dropbox for Business team, only the admin on the team can change your email address for your work Dropbox.
When you’re signed in to both a personal Dropbox and work Dropbox on the website, you’ll still be able to change the email address associated with your personal Dropbox. However, if you go to your account settings and click on your work Dropbox tab, you’ll see this message: "Please email your admin if you’d like to change your email address."