Login to your cPanel account.

https://brienne.zebrahost.net/cpanel

In the Files section, click on the File manager icon.

cPanel file manager will open. select the appropriate domain name or folder location and press the Go button.

Navigate to the directory where your file is located.

Right click on the file and then on the Edit or Code Edit in the Context Menu.

If the small Code Editor window is open, click on the Edit button which will open a new window with options you can edit.

Make changes to your file and then click on the Save Changes button.