Depends on what you want to change. For your own contact information or for emergency contacts, make changes on the Account tab at explore.garmin.com. For other contacts, make changes on the Contacts tab at explore.garmin.com.
The Explorer+ is a legacy device. You can do a wired sync with the desktop sync program. I believe you can also sync data via the old Earthmate mobile app. I no longer have an active legacy device, so I can't actually try the mobile sync path.
