Unity - Scripting API:

public static function LongField(position: Rect, label: string, value: long, style: GUIStyle = EditorStyles.numberField): long;

public static long LongField(Rect position, string label, long value, GUIStyle style = EditorStyles.numberField);

public static function LongField(position: Rect, label: GUIContent, value: long, style: GUIStyle = EditorStyles.numberField): long;

public static long LongField(Rect position, GUIContent label, long value, GUIStyle style = EditorStyles.numberField);

Parameters

position	Rectangle on the screen to use for the long field.
label	Optional label to display in front of the long field.
value	The value to edit.
style	Optional GUIStyle.

long The value entered by the user.

Make a text field for entering integers.