"ico" is a common extension for an icon. An icon is the image you see in a file browser or on your desktop. That icon will represent a file.
An icon.
.ico
first make your icon in paint then save as an ordinary file (.jpg) then use the online tool , favico maker and upload your image. The online tool will make it an icon file then it gives you the option to download it
An computer icon is collection of programs or futures that displays in a single file that display as icon
A widget is a screen graphic or icon. A file widget, also known as a shortcut, is an icon containing a link to a file. Clicking it causes the file to open.
shortcut
The way I always do it is - right-click the icon and left-click properties. In the dialogue box that opens, there is a tab to change the icon. Remember to click Apply - then OK.
If it is an mp3 file (the most common type for downloaded music) you can play it in iTunes or Quicktime - you can drag the song file's icon onto the iTunes icon in the dock to load it. Try double clicking on the song file's icon and see what it opens in.
An icon.
A file, folder, or program =P
You may be referring to a path or shortcut icon on the desktop that points to a specific file or program.