Open Settings > Orders > Order Numbers. Changes affect new orders only; existing order numbers stay unchanged. Order numbers are identifiers and do not use the price-format settings in General.
Sequential or random
Sequential numbers increase automatically. Enter a whole next number within the limits shown; you can move it forward, not backward. Random mode creates codes using letters and digits that avoid I, O, 0 and 1. Random orders do not advance the sequential counter. Switching back resumes that counter.
Prefix, suffix and spacing
Prefixes and suffixes are optional. Use only A–Z, a–z, 0–9 and hyphens, within the displayed length limits. The # is added automatically. Choose no separator, a hyphen, a dot or a slash between components. Padding adds leading zeros to a minimum width and never cuts digits from a longer number. Padding does not apply to random codes.
Dates and period resets
Dates use your store timezone. YYMM and YYYYMM identify a month; YYMMDD and YYYYMMDD identify a day. Place the date before or after the number. In sequential mode you can restart each new date period from the configured period starting number. Changing that starting number does not restart the current period; it applies at the next reset. Removing the date or selecting random mode turns period resets off.
The preview is a format example, not a reserved order number. Other orders may arrive before you save or create an order. When you change numbering settings, an already-used next number is rejected. Choose another number or format. Later imports can still occupy future numbers, which automatic numbering skips; numbering is not guaranteed to be gapless.
Imported order numbers
CSV imports preserve the complete order number supplied in the file. Importing the same source and order identity again skips that order without overwriting it. A number already used by a different order is reported as a conflict for that order; other valid orders can continue. Import preview is checked again when the order is written. Imports do not move your automatic numbering counter. Uniqueness is based on the complete order number within your store, across channels.
Other controls on this tab
Auto-archive requires a number of days from 1 to 365 when enabled. COD paid on delivery records the proportional merchandise collection as each shipment is delivered. The last delivery settles the remaining amount, including shipping and fees, and marks the order as paid. This records cash collection; it does not charge a card. Save changes after editing these controls.