Attachment

An attachment is a file sent along with an email message. It can include a wide variety of formats, such as Word documents, PDFs, Excel spreadsheets, images (e.g., JPEGs or PNGs), audio files, or even compressed ZIP folders. Attachments are a convenient way to share information, but there are important considerations:

• File Size – Large attachments can slow down sending, take a long time for the recipient to download, and may exceed email service limits (often 10–25 MB). In such cases, it’s better to use file-sharing services or cloud storage links.
• File Compatibility – Ensure the recipient has software to open the file type you’re sending.
• Security – Attachments can contain viruses or malware. Only open files from trusted senders and consider scanning them with antivirus software before opening.
• Professionalism – Name files clearly and use an appropriate format to make them easy for the recipient to identify and store.

Email attachments became possible in 1992 with the introduction of MIME (Multipurpose Internet Mail Extensions).

Before MIME, email could only handle plain ASCII text, so sending images or formatted documents wasn’t feasible. MIME defined a way to encode binary files—like Word documents, images, or PDFs—into a text-friendly format that could travel through email systems, then be decoded back into the original file on the recipient’s side.

So while email itself dates back to the early 1970s, attachments as we know them are only about three decades old.