Both are supported, and the right pick depends on what scans the label.
QR code — encodes URLs and longer data, and any phone camera reads it. Bigger on the label.
Code 128 — encodes numbers and text, reads with a barcode gun, and is far more compact on a small label.
Rule of thumb: phones and a link to more information, use QR. Warehouse scanners and short identifiers, use Code 128.