You can create a new file in a text editor and upload it to your GreenGeeks account using an FTP program, but if you prefer a web-based alternative, there is a File Manager built into cPanel.
To access the File Manager, log in to GreenGeeks and go to cPanel by clicking the “cPanel Login” button in the “Quick Server Login” section.
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Locate the Files section and click the File Manager option.
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Once inside the File Manager, locate the public_html directory.
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To Create a New File in the cPanel File Manager
Now that you are within your WordPress directory, go ahead and click on the “+ File” button.
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A small pop-up will appear asking you to enter a name for the file you are creating. Enter the name into the textbox.
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Now click on the “Create New File” button.
And that’s it. The file you created will be added to the current directory you are in. You can right-click it to edit the file.
Here are some other tutorials you may be interested in: