It's entirely possible to add one of our HTML signatures to Apple Mail, but be warned this is an advanced task and may not be suitable for all persons to carry out.
If you carefully follow my guide, you should be fine.
1. Find the code
Open your HTML signature in a browser and go to the menu bar, View, Developer and View Source, or right click on the white area and select View Source.
This will open a new tab, keep this open - we will use this later in step 4.
2. Create a signature in Apple Mail
Open Apple Mail, go to Preferences > Signatures, select your email account from the left and click the + button.
This will create a tasty looking plain-text email signature, maybe with your name and email address.
Now, Quit Apple Mail.
3. Open the signatures folder
Go to Finder. In the menu select Go > Go to folder. Then copy and paste this ~/Library/Mail/ into the field, then hit Go.
You might see V4, V5 etc. Choose the folder with the highest number, then go to Mail Data > Signatures.
4. Paste in the new HTML signature
In the signatures folder, you might see lots of files ending in .mailsignature, if you do, great! Because one of those is the one we created at step 2.
Filter by date and identify the newest .mailsignature. Then right-click > Open with TextEdit.
If you can't see TextEdit, click Other.. and choose TextEdit from the Applications list.
From <body, all the following text should be deleted (like everything highlighted in purple below)
Return to the Source Code tab in step 1 and copy the HTML code between the </head> and </html>.
Then open the TextEdit file, type the following text - <body>, [Paste your HTML code], then type the following text at the end </body> (this is highlighted in purple).
Then Save the file, but do not close the file!
5. Lock the file
Go to the Finder window, right-click the .mailsignature file and select Get Info > check the "Locked" checkbox.
6. Check it out and test
Open Apple Mail > Compose email > Select the email account (most people only have one) then choose the signature from the list that you created in Step 2.
Close down the TextEdit application and close the finder window.
If you have any difficulty completing this guide, please raise a ticket and Harry will assist you.
To benefit from this service, you must have valid time-based credit in your account.