Insert text at beginning of a multi-line selection:
- Esc to enter 'command mode'
- Ctrl+V to enter visual block mode
- select lines with up/down
- hit Shift+i and type the text you want to insert
- hit Esc, and the inserted text will appear on every line
Delete word: diw
Delete around word: daw
Disable visual mode to copy text: set mouse-=a