a) Login to CPanel of your website
b) Click on File manager so to open it
c) In file manager navigate to the folder where the file is located
d) Click on the name of the file that you want to edit
e) Click on the Edit File option in the top-right corner of your window. This will open a new window with the contents of the file displayed.
f) Edit the file as per your requirements
g) Now click on the Save changes button at your left hand side top corner when you have finished editing the file. The file has been saved and any changes will take effect from now on.