Is it possible to make a drawing from an internally saved part?
No. You will need to save it externally.
If you are talking about drawings created from virtual parts then I agree with Glenn that you cannot do this.
Yes, but it's not the ideal method.
Insert the assy into a drawing and hide all but the component to be detailed.
You can use the Hide/Show Components directly from the drawing Properties section, or use Display States or Configurations to preset a components visibility from within the assy model.
Another workaround is to make a configuration in which only the part to be drawn is located. By using configuration specific properties you can even control the configuration specific text in your drawing templates. Things like weight will update correctly.
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