Sharing this because it's the #1 question I get from people who try Moni Proxy for the first time.
The short version: you don't need a computer at all. Moni Proxy runs a local proxy on the phone itself, so the flow is:
Open the app and follow the guided setup to install a local Certificate Authority (CA) no jailbreak, no root.
Toggle capture on.
Every request your apps make shows up instantly, and you can tap any one to read the decrypted request/response body.
Because everything runs on-device, it works on cellular and away from your desk which is exactly where a lot of "only happens on the real device" bugs show up. All decryption stays local; nothing is sent to a server.