Hi @Elba ,
Welcome to our forum!
Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client and know little about HTML/CSS. To better help solve your issue, it is recommended that you post a new thread with “Office-development “tag.
I did some searching and found that Outlook uses the HTML parsing and rendering engine from Microsoft Office Word to display HTML message bodies. Read more about supported and unsupported HTML elements, attributes, and cascading style sheets properties in the following series of articles: Word 2007 HTML and CSS Rendering Capabilities in Outlook 2007 (Part 1 of 2) Word 2007 HTML and CSS Rendering Capabilities in Outlook 2007 (Part 2 of 2)
As an alternative, you can create a drop-down list in Microsoft Word through the Developer tab, then copy the entire text into a blank email message and save that as an OFT template.
More information, see: Create text with a drop-down list in Word and Copy to Outlook
(Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
Hope above can help you!
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