Add details about DPFPreviewLicenseAgreement (#682)

Author: anslpa

docs/source/user_guide/getting_started_with_dpf_server.rst

@@ -89,7 +89,8 @@ DPF Preview License Agreement
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 DPF Server use is protected using license terms specified in the `DPFPreviewLicenseAgreement <https://download.ansys.com/-/media/dpf/dpfpreviewlicenseagreement.ashx?la=en&hash=CCFB07AE38C638F0D43E50D877B5BC87356006C9>`_ file that 
-can be found on the `DPF Pre-Release page of the Ansys Customer Portal <https://download.ansys.com/Others/DPF%20Pre-Release>`_.
+can be found on the `DPF Pre-Release page of the Ansys Customer Portal <https://download.ansys.com/Others/DPF%20Pre-Release>`_. 
+``DPFPreviewLicenseAgreement`` is a text file and can be opened with a text editor, such as notepad.
 
 To accept the DPF User Licensing Agreement terms, the following environment variable must be set: