Problem: You need to change a file type without any additional software on windows.
Solution: Fix it. Follow these steps.

Note: (Change the Red Text to your preference)

First open Control Panel, Then…
1. Select Folder Explorer Options

2. Select the View tab and uncheck Hide extensions for known file types.
Click Apply.

3. The file will then display its extension.
Example: Here it’s File.txt

4. Select the file and hi the F2 key to rename your f‌ile.
Example: Here I rename it to File.xml

4. Click Yes.
File type changed.

Congratulations! You can now change file types with ease.