Builds a lightweight, table-based HTML signature with hosted images, so mail filters see text plus linked images instead of heavy embedded attachments.
A clean signature lowers the score, but most "lands in spam" cases come from domain authentication. Ask whoever manages office-2000.com DNS to confirm these three records:
SPF TXT on root
Lists every server allowed to send as your domain, e.g. v=spf1 include:spf.protection.outlook.com -all for Microsoft 365.
DKIM CNAME / TXT
Turn on DKIM signing in your mail admin console and publish the selector records it gives you.
DMARC TXT on _dmarc
Start with v=DMARC1; p=none; rua=mailto:dmarc@office-2000.com, then move to quarantine once reports look clean.
Test a real email by sending it to the address shown at mail-tester.com, which reports SPF, DKIM, DMARC and content scores together.