After creation of the vendor , i want to send the work item to 4 levels. if first approver, Rejects the work item it will goes to WF Intiator. After he corrects directly it will go to 2nd Approver . And later the remaining one by one. How can i achieve this ?
You can achieve this by building a workflow.
I am not sure what you are expecting from this forum - the forums are a place to ask for help if you have a problem, not a training ground, and not a place to post your requirements and expect people to tell you how to build your solution.
We are willing to help, but we are not paid to do so and it is only fair if you also do some work yourself - what have you tried? Which part don't you understand? Please read the [Rules of Engagement|https://wiki.sdn.sap.com/wiki/display/HOME/RulesofEngagement] if you have not already done so or are still unclear.