To do so follow the following steps:
1- Create a simple BPM process like this
2- In BPM project define business object (this will be the web service input parameter).
3- In Process Data Object define dataobject based on the created business object
4- In process Start event configure it like this
5- Select Data Associations like this
6- Deploy BPM Application.
7- You can get Web Service WSDL URL from EM.
Sometimes you will receive error message like this
If you received this message then first you have to open Service Properties
Then try to open Test Service again it should be open without errors
8- You can test web service from em as
9- After invoke web service, BPM process will start and receive data from web service and fill process object data