Outlook calls them rules, not filters. The setup lives in the web client at outlook.com (or your Office 365 / Outlook 365 web mail). Once a rule exists, it runs on Microsoft's servers — your phone and desktop both pick up the result.
You need:
In outlook.com or your Office 365 mail, click the gear icon in the top right → View all Outlook settings (the link at the bottom of the panel) → Mail → Rules.
Click Add new rule. Give the rule a name like "Forward Van Houten to Hemma".
Save. The rule fires on every new message from that sender.
Repeat for each contractor, your architect, your municipality, your insurer.

The first time a forwarded email reaches Hemma, the sender Hemma sees is you — your Outlook address — because that is where the forward came from. You are auto-approved as a project member, so it lands fine.
Some Outlook configurations rewrite the From header on forwards to look like the original sender instead. If that happens, the contractor's address will land in your Senders waiting room. Approve them once and future forwards just work.
In Outlook on the web, search for the contractor's address, select all matching messages, click the three-dot menu, choose Forward, and send to your Hemma address. Repeat per contractor. Months of build history land in Hemma in one afternoon.
My company uses Microsoft Exchange — does this work? Yes. The web client for Exchange-hosted accounts has the same Rules editor, just at your company's URL instead of outlook.com.
Can the Outlook iPhone app create rules? Yes, in Settings → Email accounts → [your account] → Manage rules. Same shape, smaller screen.
Is there a way to forward attachments only? Not in Outlook itself. Hemma already filters out signature images, logos, and any non-PDF/non-image attachments — see file size, file types, and what's scanned. Forwarding the whole email is fine; the noise is dropped before it ever reaches your project.
Will my contractor see that I forwarded their email? No. Outlook rules are silent.