If you have an iPhone, there are a few things you can do to clear all reminders on the device. This includes deleting any reminders that have been sent to the device, as well as any reminders that have been stored in the iCloud account. To delete a reminder, open the Reminders app and select the reminder you would like to delete. Then, tap on the Delete button. To store a reminder in iCloud, open the iCloud app and select the reminder you would like to store in iCloud. Then, tap on the Store button.