Grace Murray Hopper invented it
Answer:
plug-in
Explanation:
A Plug-in is a software that provides additional functionalities to existing programs. The need for them stems from the fact that users might want additional features or functions that were not available in the original program. Digital audio, video, and web browsers use plug-ins to update the already existing programs or to display audio/video through a media file. Plug-ins save the users of the stress of having to wait till a new product with the functionality that they want is produced.
The Function of a header is that it makes your TEXT LOOK BIGGER
