Tell us what you received. Copy exact values where possible.
The exact address shown in the From field, even if it looks fake.
The name shown — e.g., 'Microsoft Support' or a coworker's name.
Click a link, log in, transfer money, buy gift cards, open an attachment, reply with info, etc.
Unexpected sender, urgency/pressure, odd grammar, mismatched links, spoofed brand, request for credentials, payment, gift cards, etc.