Hi Vijay,
It depends on which apps you need. There are 300+ apps and each app has required backed level.
wave1,2,3,4 are just SAP internal release name and you do not need to know it.
Step1. Select required apps from 300+ standard apps. Apps Catalog.
Step2. Check each app and get backend EhP level and UI component name.
For example, Approve Purchase Orders, It says ERP 6.0 without EhP SP15
For example, Report Quality Issue: It says ERP 6.0 EhP7 SPS05
Regards, Masa
SAP Customer Experience Group - CEG