This information likely applies to other Hyundai models such as the i20 and i10, but I've not tried it out.
It's a bit tricky replacing the headlight bulb on an i30 at the side of the road, but can be done if your fingers are small enough. The problem is that there's not a lot of space between the headlight and the battery.
The dipped headlights take an H7 bulb, the full-beam headlights are H1.
For the near-side lights you can get a few centimetres extra space, which should be enough, by undoing the bolts on the top of the headlight housing and pushing it out a little. There are two bolts on the top, and another a bit lower down on the left. You should also loosen the bolt at the front of the battery which holds it in place, and slide the battery as far away as possible to give you a bit of extra room. Then, reach in and unscrew the plastic cap over the back of the headlight and unclip the electrical connector from the back of the bulb. You then need to undo the clip that holds the bulb in place, by pushing it in slightly, then pulling it back. The bulb can then be removed.
To replace the bulb, it's just the same procedure in reverse. I suggest practicing a couple of times with the broken one that you just removed. Of course, make sure to keep your fingers off the glass on the new one.When pushing the headlight housing back into place, make sure that the seal is well seated, and that any clips are back in position.
I've not done the driver's side bulbs yet, but it looks like they should be possible after unbolting the water bottle and moving it a little out of the way.
UPDATE - I can now confirm that the driver's side headlight bulb can be changed by unbolting the coolant filler tank and moving it to one side.View after removing the coolant filler tank
The tank is easily removed, it's held by two 10mm bolts, and can be moved to one side to allow access. Take care to keep it upright, and don't stretch or disturb the hose connecting it to the coolant system.View of the removed coolant filler tank