A drop cap is a large capital letter used as a decorative element at the beginning of a paragraph or section in a Word document. The size of a drop cap is usually two or more lines. To add a drop cap in Microsoft Word, follow these steps:

1. Select the first character of a paragraph.
2. Go to the "Insert" tab and click "Drop Cap".
3. Select the drop cap option you want. To create a drop cap that fits within your paragraph, select "Dropped". To create a drop cap that is in the margin, outside of your paragraph, select "In margin".

You can also customize the size, font, and distance of the drop cap from the text by selecting "Drop Cap Options". To remove a drop cap, select the text and go to "Insert > Drop Cap > None".