My QR code won't scan
Skip it. The same email that carries your QR code also carries a tap-to-install link and the full manual entry details. You do not need the QR code at all.
Option 1: tap to install
Open your eSIM email on the phone itself and tap the install link. No scanning, no second screen.
Option 2: enter it manually
Your email includes the SM-DP+ address, the activation code, and the full LPA string.
On iPhone: Settings, Cellular, Add eSIM, Use QR Code, then Enter Details Manually.
On Android: Settings, Network & Internet, SIMs, Add eSIM, then enter the code manually.
If you still want to scan
A phone cannot scan a QR code shown on its own screen. Open the email on a laptop or another phone, then scan that screen. Good lighting and a steady hand help.