If you find some fog lights that will fit............. I'm not familiar with the new body style... but something like this would seem to work, according to the title https://www.newegg.com/Product/Product.aspx?Item=9SIAB1H6YW3151
In any case, you get the fog lights and then wire them up. It can be a little intimidating to mess with the wiring but it's really not that bad. I'm sure the bumper is the same as older Elantra's so you'll have to remove your front bumper to install the fog lights.
Of course, that depends on HOW you want the lights to work. Factory style where you have the factory switches and the fogs turn off with the high beams takes a lot more work and more parts.
Aftermarket style where you either 1) have a fog light toggle switch mounted to turn the fogs on, or 2) have the fogs go on anytime the low beams are on is easier to accomplish. I like option 2 since I wouldn't want to have to think about turning the lights on. You can, of course, have a combination of both so that the lights are on but you have a turn off switch too.
One thing to consider is whether or not your state has vehicle inspections, and if it does then most likely they will check that fog lights operate properly, as in they turn off when you turn on the high beams.. this might not apply to all states but it does in mine, so it's worth mentioning. In that case I'm honestly not sure on what you would need to do. You'd need to figure out how to have the high beams interrupt the relay that I'll talk about in a second.
So with all that said, the actual wiring portion of the install is fairly simple.
Let's assume you want option #2, fogs go on and off with the headlights. If you get a fog light set that includes wiring or if you use a HID kit it should include a relay harness. One of the terminals on the relay will be connected to the positive wire of one of the headlight bulbs. This activates the relay whenever the headlights are on supplying power to the rest of the wiring, straight from the battery (which will also be connected to).
It's really pretty straight forward if you know the basic how to's of wiring a relay, or can follow instructions.
There might be a better way to wire it up in more of an OEM fashion, but this is the general layout of steps.