The first form of communication between companies often comes in the form of a letter, and therefore the envelope you use is vital in portraying your company’s image, along with its stationery. Envelopes come in all manner of sizes, styles, thicknesses and colours. The most common envelope sizes are; C4, C5, C6 and DL and these correspond with the most common stationery sizes which are A4, A5, A6 and compliment slip size.
Envelopes come in several different sizes like stationery.