Short answer: If your computer already has Microsoft Word, use it. If it doesn’t, install LibreOffice. It’s free and opens Word documents.

To install a program from this page on Windows, see How to Install a Program.

Officially Supported

Microsoft Word

Pros:

• Generally familiar to most users
• Online browser-based version is free

Cons:

• Desktop version is expensive
• Online version may not be feature-complete, or features may be locked behind a paid 365 subscription

How to install:

• Windows: Official installer
• Linux: Browser version

LibreOffice

Pros:

• Free
• Compatible with Microsoft formats

Cons:

• Documentation is not always up to date
• Compatibility with Microsoft formats is imperfect

How to install:

• Windows:

  winget install -e --id TheDocumentFoundation.LibreOffice

• Linux:

  flatpak install flathub org.libreoffice.LibreOffice

Unofficial Recommendations

WPS Office

Pros:

• Free
• Generally better compatibility with Microsoft formats than LibreOffice

Cons:

• Developed by Kingsoft, a Chinese company; consider data-privacy implications before using it for sensitive documents
• Frequent prompts to upgrade to paid products

How to install:

• Windows:

  winget install -e --id Kingsoft.WPSOffice

• Linux:

  flatpak install flathub com.wps.Office