If you signed up with an email and password, you can change your email address from your settings. Go to your dashboard, open settings, and click "Change email". You will be asked to enter your new email address and your current password to confirm the change.
If the email is not changing, it may already be taken by another Buildpad account. All email addresses are unique. If the email address you are attempting to update to is already taken, you may have previously created another account with that email address.
If you signed up with Google, there is no "Change email" option in settings. Submit a support request and we will help you move your account to a new email address.