🔹 What is a File?
A file is a collection of data or information stored on a computer.
Every file has:
-
A file name (e.g.,
report,photo) -
A file extension/format (e.g.,
.pdf,.jpg,.docx)
The file extension tells your computer:
-
What kind of data is inside the file
-
What program should open it
🔹 What is a File Format?
A file format (also called file type or extension) defines how data is saved and which software can open it.
For example:
-
.docx→ Word document -
.jpg→ Image/photo file -
.pdf→ Read-only document (like a printed page)
🔹 Common File Formats — by Category
📝 Text Documents:
| Extension | Description | Opens With |
|---|---|---|
.doc / .docx |
Word document | Microsoft Word, Google Docs |
.txt |
Plain text | Notepad, TextEdit |
.pdf |
Read-only document | Adobe Acrobat, browsers |
.odt |
OpenOffice document | LibreOffice, OpenOffice |
📊 Spreadsheets:
| Extension | Description | Opens With |
|---|---|---|
.xls / .xlsx |
Excel spreadsheet | Microsoft Excel, Google Sheets |
.csv |
Text-based spreadsheet (comma-separated values) | Excel, Notepad |
📸 Images:
| Extension | Description | Features |
|---|---|---|
.jpg / .jpeg |
Photo image | Small size, good quality |
.png |
Image with transparency | High quality, no compression loss |
.gif |
Animated image | Supports animation |
.bmp |
Uncompressed image | Large file size |
🎥 Videos:
| Extension | Description | Use |
|---|---|---|
.mp4 |
Most common video format | Online videos, mobile |
.avi |
Older high-quality video | Movies |
.mov |
Apple video format | QuickTime, iOS devices |
🎧 Audio:
| Extension | Description | Features |
|---|---|---|
.mp3 |
Most popular audio format | Compressed, small size |
.wav |
High-quality audio | Larger file size |
.aac |
Apple audio format | iTunes, iPhone |
🗜️ Compressed (Archive) Files:
| Extension | Description | Opens With |
|---|---|---|
.zip |
Compressed file or folder | Built-in (Windows/macOS) |
.rar |
More powerful compression | Requires WinRAR or 7-Zip |
🔹 Why Do Different Formats Exist?
-
🧩 Different purposes — text, photo, video, audio, or data
-
🎯 Compatibility — not all programs/devices support all formats
-
🗜️ File size — some formats are smaller, ideal for email or web
-
🎨 Quality — some formats preserve high quality, others reduce it
🔹 How to Identify a File Format?
The file extension appears after the dot in the file name:
-
document.pdf→ PDF document -
picture.jpg→ Image file
📌 Tip:
In Windows:
-
Open File Explorer → Click View → Enable "File name extensions" to always see formats
🔹 File Format Comparison (Quick Overview):
| Format | Type | Editable? | Common Use |
|---|---|---|---|
.docx |
Word Document | ✅ Yes | Reports, essays |
.pdf |
Read-Only Document | 🚫 No (usually) | Contracts, eBooks |
.jpg |
Image | 🚫 Not easily | Photos |
.png |
Transparent Image | ✅ Yes | Logos, graphics |
.mp3 |
Audio | 🚫 No | Music |
.zip |
Archive | ✅ Extract only | Bundled files |
🔹 Summary:
-
A file contains data.
-
A format shows how that data is stored and which program can use it.
-
Choosing the right format makes sharing, editing, and opening files easier.