Every bank gets to implement it differently. The Zelle app on my phone just tells me to open my bank's app and do it there. You can send money to someone who doesn't have Zelle and they'll get an phishing-esque invite email or text.
The worst aspect is that scammers can send you money that does bounce back (because it was an unauthorized transfer from another victim, the one scenario in which they'll reverse transactions), but your money doesn't bounce back because it was authorized.
The worst aspect is that scammers can send you money that does bounce back (because it was an unauthorized transfer from another victim, the one scenario in which they'll reverse transactions), but your money doesn't bounce back because it was authorized.