Step 1. Log into Plesk 

Step 2. Click on File manager Or you can click on Files 

Step 3. Select the folder on your left that you would like to Edit > then Click on the arrow and Select Edit and text Editor 

Step 4. Type in the necessary information and then click on Save 

Step 5. Lets edit the same file using an HTML editor 

Step 6. Type in the necessary information then Click on Apply