Currently, Dex supports adding text with the styles: Bold, Italics, Numbered List, Bulleted List, and Hyperlinks. Simply highlight the text and change the style in the toolbar. You can also use the common shortcuts:
Bold: Ctrl + B
Italics: Ctrl + I
Adding a bulleted list can also be done by typing a short dash "-" followed by a space. A numbered list can be added by typing "1." and pressing the Spacebar.
Tag other contacts in an interaction on a contact's timeline by using the "@" symbol. Typing "@" brings up your list of contacts and you can simply type to search.
Tagging another contact will automatically add your current note to your tagged contact's timeline.