In the Project Settings' General tab, under Workgroup, you can select the source control plug-in you want to use with the current project. Wwise includes a Perforce plug-in, and a Subversion plug-in.
If you don't see the plug-in you were looking for in the list of plug-ins, it may be because something is missing on your computer. For example, for the Perforce plug-in to appear in the list, you must have Perforce installed. For the Subversion plug-in to appear (in versions that include that plug-in only), you must have a compatible version of the Subversion command-line tools installed, and Subversion's "bin" folder must be in your "PATH" environment variable. Refer to the Wwise documentation for more details.