When I open the email that was sent from my MailWizz account it shows me the name of the mailing list that has been used in gmail. How can I hide that? I want to hide it because the email will be perceived as a bulk email:
That is the list header, which is indeed added by MailWizz, it is a requirement for bulk email senders.
If you search these forums, you'll find a way to also remove that header, its been discussed before a couple of times.