Transferring data

If I trade my old iPhone for the new 14 pro, how can I transfer my data to the new phone. Would they. have me do a quick start transfer at the actual apple store with an employee? Or does iCloud back up work so that I can use it on the new iPhone. I know there's an eSim so im not sure whether or not they would transfer it for you while you're at the store or whatnot. I personally wouldn't want the phone to be unboxed as I love unboxing apple products myself. How does this work?