Hi
It does not matter.
A camera, any camera, has only so many pixels it can record. Change of resolution does not change this. So if your camera produces, say, 3264 x 2448 pixels this will remain the same at 72 pixels/inch or 300 pixels/inch the only thing that changes is the dimension of the image, namely at 300 pixels/inch the available pixels will be bunched together more tightly if you will and therefore reduce the size of the image. (What people refer to as high resolution for printing).
I don't know of any camera that records JPGs at higher resolution than 72 pixels/inch. Your friends when they give you a file with 300 pixel/inch they merely have converted the available pixels their cams produces from 72 to 300 pixels/inch and thereby reducing the size of the image from 45.33 x 34 to 10.88 x 8.16 inch in the above pixel count. You do the conversion in a graphics manipulation program. And if you print at 300 pixels/inch (240 - 300 is what printers usually work with) 10.88 x 8.16 inch is what you finish up with. If you wish to print a larger size picture from the above example, as soon as you go above the 10.88 x 8.16 size restriction, in simple words, you are stretching the available pixels into a bigger space and your picture becomes blocky. Or if you want to avoid this you have a small margin to play with by reducing the resolution to 240, go lower and you are not talking high resolution anymore.
So as you can see 72 or 300 pixels/inch, it does not matter, what matters is at what resolution you want to print and then convert to that requirement.
There is a good link explaining it here:
Explaining Digital Image Resolution, Effective Resolution and How They Affect the Appearance and Quality of Digital Images when Printed
Greetings