Having a consistent and agreed email signature on email sent from your organisation is a valuable tool for compliance with any legal obligations you may have as well as an opportunity to convey your organisations branding for marketing purposes. It also contains useful information that the recipient may require for further communication with your organisation.

The Problems

There are numerous ways to add such a signature to the many email clients available, whether they be web based or applications installed on your client computers and devices. Their ease of use and features will vary greatly but the main thing they have in common is the requirement to add the signature for each person in your organisation and usually this needs to be done on each device or web mail interface that they wish to use. This can be a long process if you need to do this for many members of an organisation as some sort of I.T. support role. It can also be complicated for non-technical members to perform for themselves and requires detailed instructions to ensure a consistent signature is adopted by all.

When using images such as a company logo in the signature it is also common that this is sent as an attachment with each email. To me this seems like a bad idea, as a recipient I do not really want to store multiple copies of logos in my email storage space.

If any of the important information included in the signature is to change for any reason including relocation or rebranding the changes will need to be adopted by all members.

The Solution

An organisation wide email signature that can be administered from a central location is therefore a desirable tool. I found myself with just this requirement whilst volunteering for a charity. The charity has a few hundred email users all working from home on their own devices. The email system in use was Office 365 now called Microsoft 365, with the cloud version of Microsoft Exchange Server. This example with BYOD (bring your own devices) really showed the issues of different signatures and different setup. With users working across the Outlook Web Access client, various email clients on Mac and Windows desktops and a mix of Android and iOS /iPad OS tablets and mobile phones.

My research quickly found a selection of addons for Microsoft 365 but unfortunately, they were costly which for a charity is not a desirable option. Researching further I found the option to append a disclaimer to all emails being sent from the Microsoft 365 tenant. I began to experiment with this function to see if I could build a suitable signature for the charity.

HTML Email Signatures

First, I had a design for a signature that I had created in HTML. Writing email signatures in HTML is probably even more fraught with incompatibilities than trying to make a web site work correctly across all platform and browser combinations. Unfortunately, as well as there being so many possible email clients that your signature could end up arriving on the average rendering engine is not as good as the ones found in web browsers. Research into this subject further and I quickly realised that the key was to keep it simple and designing email signatures was a bit like writing web pages years ago. Styling needs to be included with the code not in external style sheets and layout kept simple or by using tables for layout.

Signature Images

Images need to be hosted externally and linked to from within your HTML signature code. If your organisation has a website and you have access to it, a folder on the website can be a convenient location to store a logo and any other images that you may require for the signature. This solves the issue of having a single image linked to by all the signatures and not attached to every message sent.

Signature Customisation For Users

The next issue was to customise the signature for the individuals using them, with user specific information such as name, position, email address and phone numbers. Luckily Microsoft 365 supports user variables that are taken from the information used to create the accounts. I believe this also works with on premise versions of Exchange Server with the information drawn from the Active Directory. Variables are entered into the HTML where you would require the piece of information specific to your email user and take the form of %%DisplayName%% A search on the web will find lists of suitable variables, at the time I was not so lucky and had to resort to some trial and error to find suitable variable names for my requirements.

Example Variables

%%DisplayName%%
%%FirstName%%
%%LastName%%
%%PhoneNumber%%
%%OtherPhoneNumber%%
%%Email%%
%%Title%%

Sample Signature Code

 
<!-- [if (mso)|(mso 16)]>
<style type="text/css">
a {text-decoration: none; !important}
</style>
<![endif]-->
<body>
<p><font style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif; color:#333;">
<p><font style="color: #0066B2; font-weight: bold; font-size: 16pt">%%DisplayName%%</font><br>
<font style="color: #333333; font-size: 11pt; font-weight: bold">%%Title%%</font></p>
<a href="http://www.domain.com"><img src="https://domain.com/emailsig/logo.png" width="300" height="100" border="0"></a>
<p><font style="color: #0066B2; font-size: 13pt; font-weight: bold">Organisation Name</font><br>
<font style="color: #333333; font-size: 11pt">Biglong street <br>Somecity<br>Greatcounty<br>XX1 2YZ</font></p>
<p><font style="color: #0066B2; font-size: 13pt; font-weight: bold">Tel:</font><font style="color: #333333;font-size: 13pt">%%PhoneNumber%%</font></p>
<p><font style="color: #0066B2; font-size: 11pt; font-weight: bold">Email:</font><font style="font-size: 11pt"> <a href="mailto:%%Email%%" style="text-decoration: none; color: #333">%%Email%%</a></font><br>
<font style="color: #0066B2; font-size: 11pt; font-weight: bold">Web:</font><font style="font-size: 11pt"> <a href="https://www.domain.com" style="text-decoration: none; color: #333">www.domain.com</a></font></p>
<p><font style="color: #333; font-size: 8pt; ">This email, and any attachments are intended solely for the addressee, and may contain privileged and confidential material. If you are not the intended recipient any reading, dissemination, copying or any other use or reliance is prohibited. If you have received this email in error please accept my apologies and notify me as the sender immediately by email and then permanently delete the email.  The integrity of email transmission cannot be guaranteed. Although the organisation has checked this email for viruses you should complete your own virus scan before opening any attachments.</font></p>
</font>
</p>
</body>

Here you can see the sample code displayed in a web browser. The variable names are shown but will be replaced with user specific information once this is sent as a signature by the Exchange Server. The missing image for the logo will also show once a real location is given where the logo exists.

Adding The Signature

With the email signature created in HTML and the suitable variables in place to customise the signature to individual users and images saved to a remote location. Signature can be added through the Exchange Admin section within the admin tools at office.com. You do of course need to have administrative permissions to your organisations Microsoft 365 tenant.

In the Exchange Admin Center locate the and expand the Mail Flow section to reveal the Rules options.

Add a new rule and name it. The rule needs to be applied if the sender is located inside the organisation and the action is append the disclaimer. It is possible to change these options for more specific requirements if you for example needed a different signature for certain users.

Click to open the edit box for the disclaimer and add your prepared HTML signature complete with links to external images and user variables as required.

Testing The Signature

Once the email signature is added you can test it. This is where you will notice the major disadvantage of this free method. Because the signature is appended to the emails by the server when the message is processed and sent it is not visible to the end user while they are composing their emails. This has the potential for them to feel the need to add a signature until they become happy and confident that the signature will be added for them and will be visible to the recipient of their email.