Modify Admin Task, can we customize the screen for a listed users , from radio button[Single user selection] to check box[Multiple users selection].
If yes, please suggest how we can select multiple users in a ModifyUser Admin Task...
No you cant modify multiple users at same time with modify user task. Modify user task's subject can only be one user.
However, I can share a couple of ideas with you.
1. Use Bulk Loader to call modify user task. Here you will have to supply users in csv file.
2. If you want to do this interactively from UI, you will have to design a dummy modify user task or modify group user where you can ask administrator to fill multiple user ids in a multi-valued field. Then upon completion of this dummy task you can call PX to make SOAP calls to modify user task for all users you entered into that multi-valued field.