Test Account

The best way to get a test SAP S4 HANA is from an existing SAP S4 HANA customer. If you don't have access to such account, you can get a free trial here: https://www.sap.com/products/erp/s4hana/trial.html.

You will not be able to use API with this trial - you will have to use the sandbox described below.

API Access

If you have access to a SAP S4 HANA account, you only need a username, password, and Service URL to access the API.

If you do not - you can use the sandbox provided by SAP. You can find it here: https://api.sap.com/package/SAPS4HANACloud/overview. To connect to Sandbox via integration.app, keep the username and password empty, and use the following Service URL: https://sandbox.api.sap.com/s4hanacloud

You should use API Key authentication and use API key that SAP gives you: