Sis forStickytape
You type when you use your fingers to press letters on a keyboard. The letters you type then appear either on the paper in the typewriter or on the screen of the computer that you are using.
Typing is an alternative to writing.
Tis forTypewriter
Before computers, if someone wanted to write a letter that wasn't handwritten they used a typewriter.
Typewriters work by hitting a ribbon full of ink with a small piece of metal with a letter shape on it when you press the keys on the typewriter keyboard. This leaves the mark of a letter in ink on your piece of paper.
Wis forWhiteboard
Xerox is a company who make photocopiers and printers, among other things. Their photocopiers were so widespread at one stage that the word Xerox was used to mean any photocopier, or any photocopied piece of paper.