Is the 30w usb-c adapter compatible with iPhone11?
Is the 30w usb-c adapter compatible with iphone11? if so do i have to get an additonal piece for it?
[Re-Titled by Moderator]
It is compatible and can be used with the cord that came with your iPhone 11.
Also see the Compatibility section of 30W USB‑C Power Adapter - Apple if still in doubt.