There are two ways to start a multi-line edit. You can select a range of lines, then choose Text > Blockedit Selection . Alternatively, you can hold down the option key while dragging out a multi-line selection.
While in multi-line edit mode, any text you add will be added at the same column in every line in the block.
Multi-line edit mode will remain active as long as the text insertion point remains in the selected block. Moving the insertion point out of the block, or clicking outside it, will end multi-line editing. You can also press the Esc key to end multi-line editing.