what are the differences between se01 se09 and se10 ?
SE01 is the main screen of the Change and transport Organizer. From here the administrator can acheive all tasks related to transport requests - such as create, change, view logs, display client/delivery transports, etc. SE09 and SE10 can also be accessed from here. However, not all developers might be granted access to this transaction.
SE09 is the workbench transport requests transaction - here the developers can track changes to all ABAP workbench objects (dictionary, reports, module pools, etc). This is a developer-specific transaction and mostly all developers have access to this transaction.
SE10 is the customizing request display transaction - this displays all the customizing requests in the system. Again, this could be restricted to Business analysts if required, since they would be doing most of the customizing changes in the system.