Adding a new field to 'Proposal Submitted Page'


I am a beginner to sage crm. I played around with the application but I wanted to add a new field "probablity%" onto proposal submitted page. I tried for inline customization,but I am not able to see inline customization that page, whereas it was available in the opportunity summary,edit pages.

Also, I wanted to add field constraints for phone number. i was able to do the same in "find person" page but not on the other pages, which has the phone number splitted into area code and number(3 boxes).

Can someone guide me on this please?