The email question is a hidden question that populates the email address of the signed in user who is filling out the form. Please see this link for more information. If you would like a user to enter their own email (say for a public form) you can use a text question and set the constraint with a regular expression to match the format of an email address. Please see this post for reference.
The barcode question uses the devices camera to scan barcodes and extract information from it. In Surey123 Connect there is a barcodes sample that can be used for reference