A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage.
A computer file is a specific piece of data that is held on a computer system.

File details refers to file size, file type, create time, read only etc. We can view file details right clicking the file and select properties. Shortcut: alt + Enter.

File compression lets you make the size of files smaller.
This is useful when you need to save space on a disk or when you are sending a file as an email attachment and you want to keep the size of your attachments as small as possible.

HTTP: Hyper Text Transfer Protocol.
FTP: File Transfer Protocol.
WWW: World Wide Web.

a search engines holds information about pages on websites throughout the internet. It has only information about websites which have been to it, or ones that it has found out about automatically. Ex. Google, Bing, Yahoo etc