Alternatively referred to as a caret, a cursor or text cursor is a blinking horizontal or vertical line ( ) that indicates where new text starts when you begin to type. For example, below is an empty text box, clicking in this box gives you a text cursor to indicate you can start typing.
If your text cursor is a block or rectangle instead of an I-beam, press the Insert key.
Text cursor example
As you start to type, the text cursor stays at the end of the line. Pressing the left arrow key moves the cursor to the left and allows you to insert text at the text cursor's position. You can also click with the mouse where you want the text cursor to appear in text that already exists.