I found a phishing email in my inbox that has my email address in the From: field, and an unknown email address in the To: field. It was made like I had sent the email to the unknown email address.
I'd like to ask if it is possible to change the To: field in the email header? (I know it's possible to change the From: field in email)
Your email address was probably in the Bcc field.
If you don't see your email address in the To: or Cc: fields of the header, the sender has probably mailed you a 'blind carbon copy,' or Bcc:. The Bcc: field isn't displayed in the header of received messages. This means that you won't see your email address at the top of any message you receive as a blind carbon copy.
Quoted from Receiving someone else's mail