Just like the brightly colored makers in real life, on-screen highlighting can serve a purpose to call readers' attention to something specific in their document. When a Microsoft Word document is already broken up into columns, highlighting is a way to distinguish between those columns. Highlighting columns in Word is no different than paragraphs or even regular pages of text.
Open Microsoft Word. Click the "File" tab. Click the "Open" option and navigate to a document with columns. Double-click the file name. When the document opens in a new window, scroll to the page with the column to highlight.
Click the cursor to the left of the first letter or character in the column. Hold down the left mouse button. Drag the cursor to the right of the last letter or character in the column, so the entire column is highlighted. A small, hovering pop-up window of tools appears over the highlighted area.
Click the "Text Highlight Color" button, which has an "ab" icon and a yellow underline unless another color was used within the document. This highlights the column in the Word default of yellow. To change the highlight color, click the drop-down arrow by the "Text Highlight Color" and choose another colored square. The column is now highlighted.