.chm files were once a popular and widely used file format, often serving as Help files. However, they are now mostly replaced by the more convenient PDF format. If you need to open a CHM file on Win 10, check out the methods below.

1. Opening .chm files by default on Windows 10
On Windows 10, Microsoft has provided built-in software to swiftly and efficiently open .chm files.
Step 1: Right-click on the .chm file and select Open With to choose the software to open the file with.

Step 2: Next, locate the Microsoft HTML Help Executable (1) software and choose Always use this app to open .chm files (2) to consistently use this tool for opening .chm files.
Finally, press OK to confirm.

Step 4: Congratulations, you have successfully opened the .chm file on your computer, and now you can view its contents.

2. How to open .chm files using Fly Help software
Fly Help not only allows you to open .chm files but also enables you to intervene, edit, and create new .chm files if necessary.
Homepage: http://www.flyskysoft.com/
Step 1: Visit the homepage to download the software to your computer and install it.

Step 2: On the main interface of Sky Help software, select File -> Open CHM File… to choose the .chm file you want to open on your Windows computer.

Step 3: Congratulations, you have successfully opened the .chm file on your Windows computer quickly and efficiently.

3. Converting .chm files to .pdf
If you need to professionally and simply convert .chm files to .pdf on your computer, you can use various online tools.
Homepage: Zamzar
Step 1: Visit Zamzar's homepage and select Add Files… to upload the .chm file you want to convert to .pdf.

Step 2: Once the .chm file is uploaded to the system, click Convert Now to begin the conversion process.

Step 3: Finally, select Download to save the .chm file converted to .pdf to your computer.

In this article, Software Tips has guided you on how to open .chm files on Windows 10 and convert .chm files to .pdf quickly and efficiently. Have a great day!