A column that holds two facts, like "Okafor, Amara" or "Austin, TX", is hard to sort, filter or match. Split Column > By Delimiter cuts it at a character you choose and puts each part in its own column.
You choose the delimiter (a comma, a comma and a space, @, a custom character) and where to split: at each occurrence, at the left-most one, or at the right-most one. The new columns are named after the original with .1, .2 and so on, so the next step is usually a rename.
Use the exact delimiter: splitting "Okafor, Amara" at a plain comma leaves a space at the start of the first name.