If you want to move, copy or format text in a Word document, you need to select it first.
There are several ways of doing this:
1. Hold down the Shift key.
To select text, just add the Shift key to all the shortcuts for moving around a document. So, for example, to select the next character(s), press Shift + Right Arrow, to select the next line(s), press Shift + Down Arrow, to select the next paragraph(s), press Control + Shift + Down Arrow, etc.
2. Use the F8 key.
Pressing the F8 key puts Word into selection mode and you can just use the Arrow keys to start selecting the text. Or just ress F8 twice and it will select the next word. Pressing three times selects the sentence. Four times for the paragraph and five times for the whole document. Press Escape to get out of selection mode.
3. Select the whole document by pressing Control + A.
When using the Shift or F8 shortcuts above, first make sure you position your cursor at the beginning of the text that you want to select (or at the end of the text, depending on the direction you are moving).