The webMethods attribute of a call activity informs you about the type of referenced process it refers to:
ARIS process: The call activity refers to a process in the ARIS Repository.
Dynamically invoked process: The call activity refers to a process that is determined during runtime and is unknown to ARIS. However, it may exist in the ARIS Repository.
Technical process: The call activity refers to a process that does not exist in the ARIS Repository.
The attribute has automatic occurrences in ARIS. If an ARIS user of a call activity with an occurrence of this attribute assigns a BPMN collaboration diagram (BPMN 2.0), the attribute will be deleted automatically.