No. The virtual webcam of OBS Studio is an output feature for live video created within OBS. In addition to the traditional outputs (streaming and saving as file) the video is directed to the Windows webcam API.
However, to send from external apps, just run OBS, then capture that external app with an appropriate source within OBS (usually window capture, or display capture, or game capture), then use the OBS virtual webcam to make the captured video available as webcam.