You have chosen the market, asked for their Writers' Guidelines and produced something appropriate for that market's readers. Now you need to convince the Editor it is worth reading and then publishing.
First Appearances are critical.
Use a new manilla envelope, big enough to hold the unfolded manuscript. Include the right postage and a stamped self-addressed envelope. Address it to the correct Department or Editor. Most Editors prefer a typed rather than handwritten manuscript. It should be double spaced and printed on one side of reasonable quality A4 paper.