mail, missing packages, unwanted notes, someone lingering near the door, or attempts to get you to scan a code or provide account information all deserve more care. The FBI’s phishing guidance explains that spoofed communications and links can be used to collect sensitive information, and it recommends looking up contact details yourself rather than using information supplied in an unsolicited message https://www.fbi.gov/how-we-can-help-you/common-frauds-and-scams/spoofing-and-phishing.
If you believe mail or packages were stolen, use the Postal Inspection Service reporting path. If there is immediate danger, contact local