How to add a submit button

Answer 1

<input type="submit" name="submit">

*edit*
By default, the button name will be "submit." As Wondwosen pointed out, you can change that default text by changing the value property.

Answer 2

<input type="submit" name="submit" value="Submit">
Text to be displayed on the button is inserted in value property.

Answer 3

<input type="submit" value="Submit" />