Professional Email Etiquette — Subject, Body, Signature

Why Email Etiquette Still Matters

Email is the most-used writing format in the office, and it's also where the gap between strong and weak writers shows up most clearly. The reader sees the same information either way — but a well-written email gets handled in five seconds, while a poorly written one needs to be re-read twice. This guide covers the basics that work in both Korean and global office contexts.

Subject — Pack Topic, Date, Request Into One Line

The subject line carries more weight than the body. People scan their inbox by subject and decide what to handle now versus later. A strong subject communicates as many of these as possible in one line:

What category ("[Q3 Report]" or "[Project Atlas]")
What it's about (the key topic word)
What you're asking (review, decision, scheduling)

Good: [Q3 Report] Please review by 4/30 — Min-su Kim Bad: Hi, Quick question, Report

When replying, keep the Re: prefix to maintain the thread. Start a new email when the topic changes — chaining unrelated topics into one thread is the most common reason emails become un-searchable later.

Body — Greeting, Context, Ask, Close

A four-part structure rarely fails:

Greeting — "Hi [Name], I'm Min-su from the Marketing team." Include your team and name on first contact; drop the formality with people you write often.
Context — One or two sentences linking back to whatever the reader needs to remember. "Following up on the meeting last Friday..."
Ask — The actionable part. Use bullets or numbered lists for multiple items. Bold the deadline or the decision you need.
Close — Make the next action explicit: "Could you reply by Friday?" or "Let me know if you need more detail."

For long emails, add a one-line TL;DR at the top. "Summary: please confirm the budget by 4/30." That single line decides whether the rest of the email even gets read.

Signature — One Block, No Decoration

Set up a signature once and reuse it forever:

Full name (Korean and English if applicable)
Company / department / title
Mobile (optional), direct office number
Email address
Office address (optional)

Skip the inspirational quotes, fancy fonts, and large images — they read as unprofessional in serious correspondence. A plain black text block is the safest format.

Attachments and Replies

Name files like 20260430_Q3-report_KimMS.pdf — date, topic, author. Avoid final.docx or final_v2_FINAL.docx.
Mention the attachment in the body so the reader doesn't miss it.
For files over 10 MB, link a cloud drive instead of attaching.
Use "Reply All" only when everyone truly needs the update. Default to a regular reply.

Five Common Mistakes

Mixing To and CC — decisions go to the To line, FYI goes to CC. Mass-CC reads as "this isn't my problem."
Inconsistent tone — pick formal or casual and stay there for the whole message.
Overusing emojis — fine internally; rare in external emails.
Late reply, no acknowledgment — open with "Sorry for the delay," then move on. Don't pretend the gap isn't there.
No out-of-office — set an auto-reply for any absence longer than a day. It saves the reader from wondering whether you've seen their message.

Final Thought

Email etiquette isn't a list of rules to memorize — it's the visible result of caring about the reader's time. Subject for priority, body for substance, signature for follow-up. Get those three right and your inbox starts to feel like a place where things actually get done.