Make a file read-only to prevent changes

Read-only files have special property that their contents can't be modified, instead it can be read.
These files can also be copied, moved, renamed or deleted.
Following is the step-by-step procedure to make a file read-only:-
Step 1: Right click on the file you want to make it read-only and click Properties.

Step 2: Select General tab and look for Read-only check-box.

Step 3: Check Read-only box and click OK.

This way you can avoid unintentional or unauthorized changes in files.