Things You'll Need
8 1/2-by-11-inch paper -- one sheet per envelope (white or colored as desired)
Scotch tape (or similar product)
Scissors or paper cutter
A business envelope is generally referred to as a No. 10 size envelope used mostly for business or letter purposes. It is the most commonly used envelope. The size of the envelope is approximately 4 1/8 inches wide by 9 1/2 inches long. Being able to create these envelopes from a simple sheet of paper is both economical and practical and accepted by the postal service.
Take a sheet of 8 1/2-by-11-inch paper and cut it down lengthwise to 9 1/2 inches using either scissors or a paper cutter. Fold the paper in half so that it is 4 1/4 inches wide and 9 1/2 inches long. Most business envelopes are white; however, any colored paper can be used for this project. The crafter on this project may want to make several of these envelopes to keep on hand to use when needed rather than making one at a time.
Tear off a piece of Scotch tape (or similar kind of tape) about 4 1/4 inches long. Attach one-half the width of the tape along the edge of one end of the envelope. Flip the envelope over and press the remaining part of the tape along the other end to close. With scissors, snip off any excess. Do the same with the other end of the envelope. You now have three sides closed with one wide opening.
Address the envelope either by hand or by computer. The postal service prefers the sender's address be written or affixed by a label on the top left corner rather than on the back of the envelope. Insert a letter, invoice or other mailing to fit inside the envelope. Seal the open end with one-half of a strip of Scotch tape (or other similar tape) along the edge and the entire length of the envelope. Flip the envelope over and press the remaining part of the tape along the other side to seal the envelope. It is ready to mail, but make sure there is sufficient postage according to postal service weight rules.