That's all done with an auto-tune or millidyne tool set up with hard/fixed pitches.
Instead of the singer bending the pitch from one note to another, the auto tuber hold the pitch to the nearest semitone pitch until it gets beyond a 50% lock in pitch and then it instantly jumps to the next pitch with no note bend in between.
The effects is actually an abuse of the tool which has become popular in rap music and other pop music. Dates back to the early MTV days when they first started adding a strategic digital stutters like porky pig into the mix. For some reason, likely just over exposure do to the over use of the tool but a ton of people with no musical talent at all trying to sing has extended the life and over use of that tool. What began as a simple pitch correction tool that saved time fixing vocal parts when mixing instead of bringing the singer back in to redo their part when it was sour, seems to be main stay by most millennials these days.
Personally I hate the dam thing. It sucks everything that makes the vocals human out and leaves behind a trail of artifacts. I've used it enough to be expert in its use but I hate it none the less. I had a drummer who couldn't sing a note without sounding sour and got allot of mileage out of the tool repairing his poor vocals. It was wors then 50 sets of fingernails on a chalk board but when I got done I could actually listen to the tracks through.
The biggest problem by far with the tool is, it makes a lame karaoke singer think they can actually sing which is truly an amazement to me.
When I first stated singing, I knew I couldn't sing well and anyone who heard me reinforced that conclusion. People aren't very good at hiding the fact you sound like a dog being slaughtered, if you aren't stupid enough to believe their lies when they are only trying to be kind to you.
The ides is to face obstacles and overcome then, not be told they don't exist or accept a crutch like those auto tune tools when its handed to you by people who know you cant sing. What you should do is take a bunch of records to the wood shed and sing your ass off until you develop a great voice so the next time you see those "friends" they have their socks knocked off by how well you sing. Sure you can try an hide behind an auto pitch tool but any trained ear will be able to hear right through it.
A well trained voice using the tool as an effect, can manipulate it to do some pretty cool things. I've heard it used on more then just vocals too. Back in the 70's when the Eventide first came out with the first extremely expensive hardware pitch correction/harmonizer unit I heard it used on the first Trebor Rabin album. There was a drum part at the end of the song where the drummer did a drum fill that took off and just kept going up in pitch until it disappeared into the stratosphere. It was like the drummer had a thousand tom toms, and kept moving to a smaller and smaller drums. No idea how long it took them to build that fill using a harmonizer. It was cool as all get out though. Made you go wow, never heard that done before.
History | Eventide
Today, nearly 50 years later its old news. beaten to death so bad, its like god, not again.
No signs the trend is going to change either. When the recording studio's went belly up and radio stations stopped getting Payola to promote the latest bands, the entire music business made a nose dive and has never recovered. That and the internet and the uncontrolled theft of music made the music unprofitable for most musicians. Even your most famous acts cant earn a living without playing live these days. Most downloadable sites only pay a penny on the dollar and even if you sold a million songs, you'd only wind up with $10k you'd need to set at least 5 times that to begin earning a living wage these days.
Any way, its pitch correction. My lead singer has one of those TC Helicon pedal units with that stuff built in. Works pretty good for live stuff. I can typically do better with a plugin when recording.