How to underscore words/phrases in notes and presentations when it comes to articles?

Solution 1:

I am a native English speaker and I would not include the articles when emphasising words/expressions – your second example is the format that I would use.

Aside: I would also not include the second "if" as the first one covers it..."this is the case if condition a is met and condition b is met" rather than "this is the case if condition a is met and if condition b is met".