Kinldy provide some reference documents for configuring the apigee with Sharepoint Online. Also help us understand how apigee can be leveraged to Sharepoint for data/content transactions with external system like ERP systems etc.
Apigee Edge can be configured as an API Proxy for any API endpoint.
Sharepoint Online does expose some REST-ful APIs, and as such, it can be proxied by Apigee Edge.
The next question is: what are you trying to do? It's easy to configure Edge as a pass-through proxy for Sharepoint or any other API. But normally people don't simply configure a proxy as a pass-through. What do you want the proxy TO DO ?