It's a letter P with a small section of the straight line in the upper left missing. The stylized P is on a modified rectangle that is drawn to look like a sheet of paper with the upper right corner creased and folded forward onto itself. The P is centered from left to right, and closer to the bottom of the page than the top.
Related to PowerPoint Icon
Related icons are the icons with matching tags, as well as all files icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors