YouTube for Windows is a free software application that allows you to watch videos on your computer. It is available for Windows 10, Windows 8, and Windows 7. To download YouTube for Windows, follow these steps:

1. Go to the official YouTube website at www.youtube.com.
2. Click on the "Download" button in the top right corner of the page.
3. Choose the version of YouTube you want to download (e.g., YouTube HD or YouTube Lite).
4. Click on the "Download" button again.
5. Follow the instructions on the screen to complete the download process.

Once you have downloaded YouTube for Windows, you can start watching videos by opening the app and searching for a video you want to watch. You can also create playlists and share videos with others using the app's features.