Since you posted this question in "Computer and technology" I assume you mean computer-related products, such as software.
Let's see:
Text editors (MS Word for example). Use: writing a letter to a friend.
Say you want to write a letter to your schoolmate and give it to them when you meet? You can use a text editor to edit your text (if you make a spelling mistake for example)
Graphics editor, such as Paint. Use: drawing a picture
For example if your friend has a birthday, you can draw and print a card for them!
And while you're at it, you can listen to music with a music player! for example with Windows Media Pla