With the advent of an Internet protocol called MIME, Multipurpose Internet Mail Extension, and other types of encoding schemes, you can send formatted documents, photos, sound and video files as attachments to your e-mail messages.
These protocols use a complex mathematical formula to convert files to text and then back to their original form. This conversion process is known as encoding and decoding. If the person to whom you are sending an attachment uses a MIME-compliant or UUencode e-mail program--and almost all programs do--it automatically detects the attachment, decodes it, and either opens it or prompts the recipient to save the file.
Before you send binary files or formatted documents as attachments, make sure that the person you are sending them to has the ability to open the files. For instance, if you send a spreadsheet created in Excel, the recipient needs that program to view the file.
By the way, don't confuse encoding a file with encrypting a file. Encoding files adds no security. Anyone with the right decoding software can view it.How to Do It
The procedure for attaching files varies depending on the type of e-mail program you use. In general, you click an icon, such as a paper clip, located on the toolbar of the program. If you use a Web-based e-mail service like Hotmail or Gmail, click "Attach" on the toolbar to attach a file. Select the file you want to attach by locating it on your hard drive or on a disk. Once you've selected the file, either its name will appear as part of the e-mail header, or as an icon within the body of your message. Most programs allow you to attach multiple files, but may limit the size of the files. (As of this writing, many e-mail services won't let you send files larger than 10 Mb.) Once the files are attached, click the Send button and off they go.
For more help, see Step-by-Step: Sending E-mail Attachments.
Last update: Jan 11, 2010