You can buy 127 film in a number of emulsions -- much of it is recut/rerolled and costs include the labor cost for that work, but Shanghai and Rerapan are factory made in 127 format. Most labs that can handle black and white can handle 127, as can most color minilab machines (if they can do both 35 mm and 120, they can handle 127).
You can also convert 120 film to 127 with a razor blade and changing bag, providing you have at least two 127 spools. You can make the cut in the light, so you can see what you're doing, and then you have to reroll the film onto the 127 spools (two step transfer to get the correct direction and trim both ends of the paper so it fits the flange diameter) in a dark bag.
The recut/reroll and processing parts are also true for 828; I wouldn't send that format out for processing, though, as you can't be certain of getting the spools back, and unlike 127, no one seems to be making new 828 spools at this time. 828 is 35 mm wide, 127 is 46 mm, so you can measure your camera to be sure which it is.