I have a need to be able to have data sent via email to us
That's existing functionality, in fact one of Machform's primary functions.
and have it password protected as well. Does anyone know if this is possible?
Not exactly sure what you mean here . Your email is already password protected (or it should be.....) You should be the only one with access - unless it is a shared mail box in a corporate environment. Normally in a corporate network you'd log onto your PC through Windows, which would then also connect in with your Outlook application and email. If using something like GMAIL, then of course you have to log into view the messages anyway, so not sure where your question is heading.
Machform has the ability to create multiple users (how many depends on your icence) so the extra users could be full admins, they could possibly only view entries, or create /edit forms or do any/all/some of the above.
it would help us if you can clarify exactly what you want password protected - the emails received (already done as stated) and also if viewing the back-end only authorised users would be allowed there, according to the permissions that are set up.
Like JCSweatt suggested, you can customise the email notifications - even to the point of not having any of the submitted data in the email - it could simply say "A new submission has been received...." or you could put the basic info like "A new submission submitted by XX [Name] through [website name] on the [form name] form. Log in to Machform to view the submission".