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    1 min read 4 stepsApril 10, 2026Verified April 2026

    Common File Types Explained: PDF, JPEG, DOCX, MP4

    What do those file extensions mean? A simple guide to files you encounter every day.

    In this guide (4 steps):

    1. 1.Documents
    2. 2.Images
    3. 3.Video and audio
    4. 4.How to open unknown files
    1

    Documents

    ~15s
    .PDF — universal document, looks the same everywhere. .DOCX — Word document, editable. .TXT — plain text, no formatting.
    2

    Images

    ~15s
    .JPEG/.JPG — most common photo format. .PNG — supports transparency, used for logos and screenshots. .HEIC — Apple photo format, high quality, may need converting.
    3

    Video and audio

    ~15s
    .MP4 — universal video format. .MOV — Apple video. .MP3 — standard music format. .WAV — high quality audio.
    4

    How to open unknown files

    ~15s
    Right-click > Open With > choose a program. PDFs open in any browser. DOCX opens in Word, Google Docs, or LibreOffice (free). When emailing, PDF is the safest choice.

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    Official Resources

    GCFGlobal — Free Digital SkillsAARP Technology TipsSenior Planet

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    Common File Types Explained: PDF, JPEG, DOCX, MP4 — Step-by-Step Guide | TekSure