The purchase order PDF - downloaded, printed, or attached to the email your supplier receives - is customized in Settings, Documents & email. Everything there is a shop-wide default, and any supplier can be given its own version.
The basics
Business name shown to your suppliers - the name your suppliers deal with, when that is not your Shopify store name. It prints on the PDF and is used in the emails they receive, including the sender name in their inbox. Left empty, your store name is used. Worth setting if you trade under a different name from the one on your storefront.
Logo - upload one and it prints in the document header.
Paper size - Letter (8.5 x 11 in) or A4 (210 x 297 mm), applied to downloaded, printed, and emailed PDFs.
Email shown on documents - printed in the PDF header. Left empty, it falls back to your reply-to address, or your store email.
Bill to - where suppliers should send the invoice, when that's not the address goods ship to. A supplier or a single order can override it.
Default ship-to address - where suppliers should deliver, when that is not your Shopify location address. It prints on every order that has no ship-to of its own, whichever location the goods are for - so leave it empty if you receive into more than one location and let each location print itself. Any single order can still override it.
A standing note on every order
Standard note on purchase orders prints at the bottom of every PO PDF, below the order's own note - the natural home for payment instructions, delivery hours, or terms you'd otherwise retype on each order. Each purchase order can still carry its own note; the two print together.
What the PDF shows
Which blocks of the document print - costs and totals, notes, images, barcodes, received status - is its own article: Choose what the purchase order PDF shows: costs, notes, images, received status. Those switches apply shop-wide, can be varied for one supplier, and can be changed at the moment you send or print.
Metafield columns
You can print up to two of your Shopify metafields as columns of their own - a season, a model year, a fabric - so a supplier picking your order can tell near-identical items apart. Choose them in Settings > Documents & email. A metafield has to be turned on under Settings > Data & sync > Your Shopify metafields before it can be a column - Stockroom lists every product and variant metafield definition there, and syncs only the ones you switch on.
A metafield column hides itself when no item on the order has a value for it, and the value printed is the current one from Shopify. Unlike the document blocks, the choice of metafield columns is shop-wide: it is not part of Customize for this supplier, and it does not appear in the PDF options switches at send time.
Good to know
Show notes governs every note on the document - the order's own note, the standing note, and the per-line notes for the supplier. Turn it off for a supplier and none of them prints on their copy. Internal line notes never print either way.
The same Settings tab holds the Supplier email template - the subject and message that accompany the PDF when you email an order.
The PDF's own labels and headings are always in English - it is a supplier-facing document, so it does not follow your admin language. Your own text prints exactly as you typed it, in any language: product names, supplier names and addresses, order notes and the standing note all print in their own script, including Japanese, Chinese and Korean. If any character comes out as an empty square, tell us which language and we will add it.