Kontakt biznesowy and other 65,000 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
A business contact icon is a rectangle, but it isn't complete because at the bottom there are two half like circles that looks like someone hole punched it. In the rectangle there are two symbols, on the left there is a person and on the right there is an at sign.