Visual mode is a flexible and easy way to select a piece of text for an operator.

Using Visual mode consists of three parts:

  1. Mark the start of the text with v, V or <CTRL-V>. The character under the cursor will be used as the start.
  2. Move to the end of the text. The text from the start of the Visual mode up to and including the character under the cursor is highlighted.
  3. Type an operator command. The highlighted characters will be operated upon.

Full documentation: visual vimdoc