This particular icon has three square boxes that are positioned on top of each other. On the side of the boxes are long lines. There are two checkmarks in the first two boxes at the top.
This Checklist icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,000 icons, all in the same style and quality.