File Extensions

File Extensions are the ending letters associated with a file and an application that it can be manipulated in. This way Windows knows to tell which program to open the file you want to manipulate. For example a text file has an extension of .txt, so a text file created in Notepad called Phone Numbers would look like this PhoneNumbers.txt ... You do not have to assign a file extension to a file that you create. The program you use will automatically do this for you. All you need to do is give it a filename. Some other common extensions are as follows:
.doc = Microsoft Word Document
.xls = Microsoft Excel Document
.ppt = Microsoft PowerPoint Presentation
.mdb = Microsoft Access Database
.bmp = Windows Bitmap Picture
.wav = Sound File
.html or .htm = Internet Document