I have a chance to get a Canon Powershot Elph 20MP digital camera for free. Is this a suitable camera for photographing models? Currently I use the camera on my iPhone. If you can't tell, I know next to nothing about cameras.

Yes.

Better than a phone - definitly

For free - take it. It's a nice point and shoot for general use. Had an earlier model (called IXUS or Powershot in D) for some time

Perfect to shoot kits - no

Usable to shoot kits - yes if one accepts/knows the limits

It has a rather large sensor - good for image quality

It has a screw for a tripod. That is good since it allows you long exposure times. Useful since:

It is not the best "low / bad light system" so you'll have to use either long times, the build in short range flash or external lights. Otherwise you get "digital noise" (High ISO values) and that is generally not good since it hides details etc. Having a Digit 4+ CPU the camera is not very good at eliminating it (Digital Noise suppression), a common "problem" with the Digit4/4+ family (used in various Canons including DSLR)

It only does JPEG. Not a problem in general (so do most phone cams) but it limits your freedom in post-processing since JPEG will loose quality every time you do a "save and reload" cycle. So start with the best quality the cam can store (Called L in Canonese) and try to get most elements right without GIMP/Photoshop/Whatever

The flash is short range (no more than 4 meters) and not a very "nice" light since it is to close to the lens. And the camera has no "hotshoe" so you can not use external flashes. OTOH a few good foto lamps and a light tent are rather cheap (There are some ideas in this part of the forum)

OTOH you get a decend "depth of field" that is large parts of the kit front to back will be "in focus". Something that users of "big cameras" have to fight for (The bigger the sensor the smaller the DoF with all other things beeing equal).

Thank you for your highly informative response. I have a lot to learn, but learning new skills is a large part of this hobby.