How are stage direction shown in a script? Is it with bold letters or italicized or with letters or underlined

Stage directions are typically shown in parentheses and are usually italicized to differentiate them from the dialogue of the characters. For example, a stage direction might look like this:

(Jane crosses the room and sits at the table)

Some playwrights may use different formatting techniques such as bolding or underlining, but italicizing is the most common convention for indicating stage directions in scripts.