HTML is used to format information in PeopleHR. The text will show normally on PeopleHR because the system reads HTML.
However, when you export comments to Excel, Excel retains all of the information in the comment as text, including the HTML formatting.
To make sure that the formatting doesn't pull through to Excel:
Avoid pasting from external sources into the PeopleHR comment section.
Don't create too many lines. Every time you press the Enter button, it creates an HTML tag.