Your jpg and png files are raster images, there is no type to outline. If your printer needs vector outlines to create a varnish or foil stamp, your best option is to find a vector version of the logo and re-set the type, then save as an outlined version of the file. The other option is to draw paths around the type by hand, but I don't recommend doing that.
Normally when a printer makes such a request it is because that printer does not have the actual fonts needed for reproduction. If you are providing flattened artwork such as a jpeg or png which makes actual fonts or even outlined versions of them unnecessary then there is no reason that I can think of that they would need outlined fonts. If the printer's issue is about resolution of the jpegs or pngs then that is something that will need to be addressed and most likely higher resolution images will need to be obtained. Ask the printer specifically why the request is being made.