The function of groups Groups is to help categorize a users's functional roles within your setup. While that sounds fairly similar to departments, there is a distinct difference between the 2two, not only from in semantics but for in functional purposes as well. The main differences between groups and departments are:
a. A group represents a functional purpose. To that reasoningThus, a user can belong to many groups while but can only being able to belong to one department.
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In short, use departments when you are trying to represent a user's placement within and an organizational chart, and use groups to represent the various functions a user might carry out.
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To manage groups, access Setup Users > Setup Groups. Note also that each group created can be tied to a specific organization (but , although not necessarily so). As mentioned earlier, a user can belong to multiple groups and, unless restricted, a group can have members that spans several organizations.