This article explains how to change the permissions of a file or folder via the File Manager Graphical interface. If you are unfamiliar with the file permissions and their corresponding names.
If you want to change the Unix / Linux - File Permission / Access Modes then Please view the link below.
Follow the Procedure
1. Log into cPanel as the user in question and locate the file or folder in question.
2. Right-click the file or folder and select 'change permissions.'
3. The permission menu uses the full wording for the permissions, read, write, and execute. For standard '644' that most files, the first section needs 'read, write', and the other two areas only need 'read'. Once this is done select 'Change Permissions.
If you are facing a problem all folders make 555 which needs 755, You just update the main folders, and inside all folders making 755 will fix your issue.