To edit your profile info, visit foursquare.com/settings. From here you will be able to edit your profile, sharing settings (to Facebook and/or Twitter), privacy, notifications, connected apps, and managed pages (for businesses).
If you have questions about who can see your information, please see this help article.
How can I change my username?
If you link your Foursquare account to your Twitter account, we'll automatically use your Twitter username as your Foursquare username. You can only change your Foursquare user ID by linking your Twitter account. Head over to Foursquare.com/settings/sharing connect your Twitter account.
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