Clicking on the Format Text button in the toolbar will expose a number of settings relating to text formatting for the editor:
Formatting can be applied to all of the text by:
Updating all formatting settings before starting a new communication
Selecting all the content of the editor via CNTR + A (CMD + A for Mac OS users) and updating the settings
Or you can choose to only update a portion of the editor text by selecting the targeted section and updating the settings
Certain text formatting settings can also be toggled via keyboard shortcuts:
Bold → CNTR + B (CMD + B for Mac OS users)
Underline → CNTR + U (CMD + U for Mac OS users)
Italics → CNTR + I (CMD + I for Mac OS users)