How to add a signature in mailbox.org
Add your email signature in mailbox.org webmail, set it as the default for new emails and replies, and fix plain-text signatures and the wrong alias signature.
If you already have a signature, copy it and follow the steps below. If you need one, make it free on Signatoro, then click "Copy signature".
Add a signature in mailbox.org
mailbox.org now calls itself mailbox, and its webmail is the mailbox Suite. To add a signature in the mailbox Suite in a browser:
- Click the gear icon at the top right, then "All settings".
- Click "Mail" in the left pane, then "Signatures".
- Click "Add new signature" and give it any name.
- Paste the signature into the text box, choose whether it goes below or above the email text, and click "Save".
- Click "Set default signature", pick it under "Default signature for new emails" and "Default signature for replies or forwardings", and click "Save".
Use "Add new signature" to keep the signature you copied. A mailbox signature template builds a signature from its own text, links, images and theme.
Change your mailbox.org signature
To change a mailbox.org signature, open "All settings" from the gear icon, click "Mail", then "Signatures", and click "Edit" next to the signature. Delete what is in the text box, paste the new signature and save it.
mailbox.org signature on iPhone and Android
On a phone, mailbox runs in the browser: use the mailbox Suite there, or install it from the browser as a web app. Either way it is the same webmail with the same signatures.
A mail app connected to your mailbox account, such as the iPhone Mail app or Outlook, keeps its own signature. Set it there too with the iPhone and iPad guide or the Outlook guide.
mailbox.org signature questions
Can I set a different signature for each alias in mailbox.org?
mailbox.org sets default signatures per email account, and aliases belong to that account, so they share its defaults. Users on the mailbox forum report that replies from an alias still get the default signature. Create one signature for each alias under "All settings", "Mail", "Signatures", then pick the right one by hand: in the mailbox compose window, click the Options icon and choose the signature from the list.
Why does my mailbox.org signature arrive as plain text?
A mailbox.org signature loses its images and colors when the email goes out as plain text. Open "All settings", click "Mail", then "Compose & Reply", and set "Message format" to "HTML" or "HTML and plain text". For a single email, click the Options icon in the compose window and turn on "HTML".
Why is my mailbox.org signature missing on replies?
mailbox.org has two default signatures, one for new emails and one for replies and forwards. If replies go out without a signature, the reply default is usually empty. Open "All settings", click "Mail", then "Signatures", click "Set default signature", pick your signature under "Default signature for replies or forwardings", and click "Save".
Where are the signature settings in mailbox.org?
The mailbox.org signature settings are in the mailbox Suite under the gear icon at the top right: click "All settings", then "Mail" in the left pane, then "Signatures". In the phone view of the webmail, open the settings from the menu icon (≡) or your profile icon instead. A mailbox news post from 2026 calls the same section "E-mail".
For agents
If you're an assistant setting this up on someone's behalf: these are the five gear > All settings > Mail > Signatures steps, in order, in the mailbox webmail. Paste the signature as formatted text, exactly as copied, through "Add new signature". Set both defaults in step 5. If the person sends from several aliases, tell them the default is per account and the signature is switched from the compose window's Options icon.
Sources
Checked against mailbox's own help pages on 2026-09-25:
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