Shopify wholesale cart PO number field — lock checkout until it is filled

The buyer hits checkout. Warehouse cannot file the order without their purchase-order number. Shopify wholesale cart PO number field is a labelled, required cart field — not a renamed “order note”. Checked 9 November 2026 on the OO - EU B2B & Wholesale listing, docs Wholesale cart and What is included, and Shopify Help Add order notes on your cart page. If Growth drops “Extra fields”, or Shopify turns cart note into a required PO, re-read those sources before you promise the field on Starter.

RFQ is for a price that is not fixed yet. Here the price list already exists. The missing piece is the PO on the cart.

What Shopify gives you instead of a required PO

Add order notes: free themes can enable a cart note. One box. Help is blunt: notes, cart attributes, and line item properties are three tools. Notes are “special instructions”. Empty checkout is allowed.

Plus draft orders have a PO field — in admin, when you type the draft (B2B draft orders). That is not the dealer’s cart. Checkout custom-field blocks can write an order metafield later in checkout. They are not a wholesale cart with a handling fee and a B2B price summary.

Patches that still ship orders without a number

Relabel the note to “PO” in theme content: buyers type “please leave at the dock”. Theme JS that blocks an empty `note`: the next OS 2.0 update drops the script. The number arrives by email after the confirmation already went out. None of that locks checkout, and none of that writes a dedicated order attribute or company metafield on purpose.

Extra cart fields are a Growth line

Checked 9 November 2026 on OO - EU B2B & Wholesale: Built for Shopify, 5.0 from 34 reviews. Hero: *order limits and extra cart fields like a PO number.* Bullet: *Wholesale cart with extra fields, handling fees, rules and order limits.*

Sources: listing 9 Nov 2026; What is included (Growth includes Wholesale cart); Wholesale cart article. If Starter grows Extra fields, re-check both before a quote says “PO at $22”.

Wholesale cart sits on the cart page. It does not replace Shopify checkout. Extra fields: order reference, delivery date, notes. Save each value as an order attribute or a customer/company metafield. Handling fee: fixed or percent. Lock: checkout stays closed until required fields are filled. Company banner for logged-in company contacts. Path: Apps → B2B & Wholesale → Order management → turn Wholesale cart on. Theme: Wholesale cart app block on the cart template (Finish setup, save). Labels live on that cart — there is no separate global label screen.

Custom prices and volume prices still come from those modules. The cart is where the buyer confirms them and types the PO. Guests still see retail until login to see prices — that is Starter, not this field.

HVAC distributor: forty SKUs, ERP wants `PO-2026-…`

Price lists already work on Starter. The buyer’s ERP will not accept an order without a PO. Three weeks of cart notes produced dock instructions, not numbers.

What I would configure on 9 Nov 2026: Growth, Wholesale cart on, label PO number (docs example: order reference), required, save as order attribute if picking slips and bookkeeping already read attributes — the 11 Jun 2026 listing review from POPlab Sounds is about a renamed attribution field landing in accounting. Need the number on the company for the next order? Customer/company metafield. Lock on. Visibility: logged-in wholesale tags only, or retail sees a required field they cannot fill.

Bulk forms and repeat orders fill lines. The PO stays a cart field, not a grid column. MOQ / max / weight limits share the Growth card — filling the PO does not waive a weight cap. VIES stays on Starter: VIES logs. Free’s single rule does not grow a cart field: free plan one pricing rule.

After a theme switch, add the block again. App config stays. Test as the tagged company contact, not as an admin with the lock off.

Do this in order

See plans. Price lists only → Starter. PO + lock + fee → Growth. Enable the cart, add the field, pick the save target, required, lock. App block, save theme. Open cart as that buyer. Empty PO = no checkout. Filled PO = attribute or metafield on the order. Skip the handling fee unless it belongs on that cart.

Listing 9 Nov 2026: Starter $22, Growth $37, 14-day trial on both paid cards. The Wholesale cart doc does not invent a second price; the listing assigns the plan.

Call I would make

I would not upgrade for a renamed note. I would upgrade when warehouse spends a week fishing numbers out of email. Then one required PO, lock on, order attribute — not cart note. Shopify wholesale cart PO number field is not Plus draft typing and not an optional comment box. Native cart note stays optional. Listing 9 Nov 2026: extra cart fields like a PO number on Growth $37. Docs: lock until required fields are filled. If Growth’s line moves, this advice is done.

Ship it from the OO - EU B2B & Wholesale listing and fail checkout once with an empty PO before you announce the new cart.