WordPress include a built-in editor which allows you for editing files directly from within your browser online which is called the File Editor that let you to edit file easily. Check few important instructions how you will go for editing your file effectively without losing anything.

This is the way you can access the built-in File Editor from the Administration > Manage > Files Panel.

* To view a file in the File Editor, click on the file from the list or type in the specific address such as
example.com/wordpress/filename.php
* If the file is “writable” you will see a button at the bottom of the editing window that says Update File. Click
this when you are done with your edits and ready to save the file.
* If the file is not “writable”, you will see a note under the bottom of the editing window saying the file is not
writable. You will need to CHMOD the file to 666 in order to make it writable through an FTP program (preferably FileZilla)
before you can edit it.
* Important instruction;

Before editing, backup your file by saving a copy!
* While making change to the file inside the File Editor window, all you have to Edit with care as to not delete or harm
the code inside the file.
* When ready to save the file, click the Update File button at the bottom. This will save the file and now you’ve done. In next article we will cover the editing process for image.