Some email clients show "on behalf of bounce.automizy.com " or "via automizy.com " in the header details of your email due to authentication.

This is a common way for email clients to verify that an email comes from a legitimate sender.

Set up DKIM and SPF records to authenticate your email address.

It makes your emails more credible, which eventually increases your email deliverability and reduces the probability of landing in spam folders.

Email clients not only check the email address in the From field but also the sender address.

The sender address is not always visible, but it is necessary to send emails through any email marketing software.

Some email inboxes display both your information and our information in the sender details of an email.

Outlook shows the name of your account, your email address and also the domain name of the mail server with “sent on behalf of” ahead.
In Gmail there is a similar message, although the wording is slightly different: "via".

This setting is determined by the email client and is not something that Automizy can control.