By default, when you create a new marketing email from scratch, HubSpot will set the "From Name" and "From Address" of your email to the creator. For example, if Jane Doe created the email, and went to send it out to the subscriber list without making any changes to the default settings, the email would be sent as from Jane Doe with the email address of jane.doe@yourcompany.com. 

While you can certainly still send emails from actual users in HubSpot, its important to verify that the email addresses you use are connected to the same email sending domain you have set up with the DKIM, SPF, and DMARC policies.
For example, if your connected email sending domain is @yourcomapny.com, you should NOT send emails using the domain @email.yourcompany.com.

To update the name and email you are using the send your emails from:

1. Navigate to the Marketing Tab
2. Click into Email
3. Select an individual email to Edit
4. Click into the Settings tab
5. Switch the name and email in the top two drop down selectors

While you can create custom from names and use an email alias, if you are going allow replies to the From email, make sure its a real email alias or address. If you want to track replies within HubSpot, you will need to connect that email address to an inbox as a dedicated channel. This approach does not allow for alias emails, it must be an email address with its own dedicated log in credentials.