Please refer to oracle metalink note - How To Do Forms Personalization (Doc ID- 468657.1)
This note contains a demonstration viewlet which explains the steps to do form personalization for the following tasks
1) How to change the Label Description?
2) How to make the field Mandatory?
3) How to Remove Certain Fields?
4) How to hide Tabs?
5) How to change tab label details?
6) How to control position of radio button?
7) How to set initial values to field?
8) How to make field’s not updatable?
9) How to Create PO with Promised date greater than sysdate?
10) How to add special Menu and Actions?