To toggle the emails and notifications you get from Quora, visit your Settings page, then click on "Email & Notifications". On this page, you'll be able to customize the types of notifications and emails you receive from Quora, as well as the frequency in which you receive them.
To do this on our mobile app, tap on your profile icon in the upper left, tap on "Settings", choose "Email & Notifications", then select either "Push notifications" or "Email" depending on which one you want to edit.
Please note that not every type of email will appear on this settings page. If you want to unsubscribe from certain emails that don't appear in Email & Notifications, please see How do I unsubscribe from Quora emails?