What do you have to give it?
Who it is for, what you want and the tone. Three fragments are enough: “email to my landlord, boiler broken five days, polite but firm”. Everything else, subject line, opening, structure, sign-off, is generated. The more specific your fragments, the less you edit afterwards.
Does it write subject lines too?
Yes, and there is a dedicated Email Subject Line tool if you already have the body and only need the line that gets it opened. There are also separate tools for replies, follow-ups, cold outreach, meeting requests, apologies and thank-you notes.
Can it reply to an email I have received?
That is the Reply to an Email tool. Paste the message, say what you want to convey, and it drafts a response that answers the actual questions asked rather than a generic acknowledgement. Decode an Email is useful first if the sender was vague.
How to keep it from sounding like everyone else
Cut the opening line. AI-written emails almost always begin with a sentence restating why you are writing, and human ones usually do not. Delete it and start with the second sentence, the email immediately reads like a person wrote it.