There is no direct way of getting an HTML email signature onto the iPhone mail app (or on iPad). You have to create the signature for a desktop app, then send it to your iPhone then copy and paste the signature into the iPhone settings. To install on an iPad follow the same instructions but substitute iPad for iPhone.
Step 1 — Install your email signature using one of the other desktop methods
- Create your email signature in Mirosign.com.
- Follow instructions to install the signature on a desktop app using any of these:
Apple Mail desktop app
Microsoft Outlook on PC
Microsoft Outlook for Mac
Thunderbird on PC
Spark Mail on Mac
Step 2 — Send yourself an email with your new signature
Step 3 — Copy signature
Open the received email in Mail app on your iPhone
Find a part of the signature text that is not a web or email link. Press and hold this text.
The context menu will appear over the text. Tap Select All to select the entire signature, then press Copy.
Step 4 — Paste signature
Navigate in the iPhone Settings to Mail > Signature (right at the bottom under COMPOSING) and then to the appropriate account text box, either All Accounts or Per Account if you have multiple accounts / signatures.
Press and hold to Paste the signature in the box below
Step 5 — Re-format signature styling
The signature will initially look a bit large and perhaps mangled or unformatted:
Now—as crazy as this sounds; shake your phone. It will act as the normal ‘undo’ feature. A box should pop up saying, ‘Undo Change Attributes’.
Click undo to return the signature to the correct size.
Return to the main screen of Mail app create a new message to check your signature is working.
more information here on how to How To Create An Email Signature In IOS Mail