The correct way to punctuate is seen in b:
<span>To whom it may concern:
</span>
In formal settings and when you don't know the exact identity of the person a dresses it is usual to use a colon in this situation.
Digital learning has taught me how to study independently. i remember during one of my online classes, i didn’t understand a thing the teacher said, hence i had to watch online videos to clear my doubts
I would write my notes in the margins, if that's what you're looking for.
Examples:
<em>A Twist of Fate
</em><em>A Twist on Fate
</em>
