Below tip helps you paste code snippets to outlook emails with syntax highlighted. To make this possible, I always use Notepad++ with NppExport plugin.
Copy the code which you would like to paste in the mail into Notepad++ and set the language type by going to Language > C# (whatever is the language of the code). Now click Plugins > NppExport > Copy RTF to clipboard this will copy the syntax-highlighted code into the clipboard. You can now Ctrl+V in outlook to get the syntax highlighting code.
How to Install NppExport if it’s not already installed
Inside Notepad++, Goto Plugins > Plugin Manager > Show Plugin Manager. Then in the Plugin Manager window under Available tab select NppExport and click Install.
Please let me know if you know any other ways to do it in the comment section below.