If you are using Apps to track business processes like You can choose to allow clients to initiate certain project apps such as help desk requests, issue / bug tracking, change requests, etc.. your clients can initiate them. Your Clients can participate in a process if they have initiated the process and it is marked as "client visible".. This can be done by keeping the "Clients can initiate" check-box checked for the App definition.
To participate in project processes:
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