A signature is a small thing that is noticed when it is wrong.
WHAT TO INCLUDE
Your name and role The business name A phone number people can actually reach The website address One or two social or professional links if genuinely useful
WHAT TO LEAVE OUT
A full postal address, unless it matters to your business Long legal disclaimers, which almost nobody reads and which look defensive on a short message Large images and logos, which get stripped, blocked or turned into attachments Inspirational quotations "Sent from my phone", which reads as an excuse
FORMATTING
Keep it plain and short. Six lines is plenty. Text with one small image at most survives every mail client; elaborate HTML does not.
WHERE TO SET IT
Webmail: Settings > Identities.
Outlook, Apple Mail, Thunderbird and phone clients each have their own, and they are separate. Setting it in webmail does not change your phone.
CONSISTENCY
Agree one format for the team and send it round as text people can paste, rather than leaving everyone to invent their own.
