Commercial customers — letting agents, facilities managers, main contractors — usually raise a purchase order before the work starts. Their accounts team then won't pay an invoice that doesn't have that PO number on it. Mucka has a proper box for it, so you're not writing it in the description and hoping someone spots it.
It's switched off to start with. Most domestic work never involves a PO, and there's no sense in an extra box on every invoice you raise if you're never going to use it.
Switch it on
Head to Settings → Business → Paperwork and tap PO numbers, under Extra reference boxes. Turn it on and hit Save.
That's it. From now on every invoice — new and existing — has a PO number box on it.
Add the PO to an invoice
Open the invoice and you'll find PO number just under the description. Type the number exactly as your customer gave it to you.
You can also just tell Mucka:
"Put PO 4471 on Hendersons' invoice."
Leave it blank on the invoices that don't need one — a blank PO doesn't show up anywhere, so those invoices look exactly as they did before.
Better: put it on the job, and let it carry through
The order number nearly always turns up before the invoice does. A letting agent or a housing association emails the works order over, you book the job in, and the invoice is a fortnight away. So there's a PO number box on the job as well, right above Notes.
Fill it in when you book the job. Then when you raise the invoice — whether you do it yourself off the job page, or Mucka drafts it for you when the work's done — the number's already in the box. You never type it twice, and you can't forget it on the day.
It also shows on the job page itself, just under the address, so when the agent rings up quoting "WKO0150617" you can find the job without opening anything.
You can tell Mucka too:
"Book Mrs Shah's legionella test for Tuesday, works order P211SC8146."
Where's the box on my jobs? It's there if you've switched PO numbers on above — or if you've got the Work Orders skill installed, since that's for exactly this kind of customer. If you've got the skill but haven't switched PO numbers on, you can still record the number on the job; it just won't print on the invoice until you turn the setting on. The box says so.
Where it turns up
Once there's a PO number on the invoice, it appears:
- On the invoice PDF, in the top-right block next to your invoice reference
- On the online pay page, so whoever opens the link can match it up straight away
- In Xero, QuickBooks and FreeAgent if you've got one of them connected
Your own invoice number (INV-001 and so on) stays exactly where it is. The PO sits alongside it — one's your reference, one's theirs.
Common gotchas
- Nothing showing on the invoice? The box only appears once PO numbers are switched on in Settings. If you switch it back off, any numbers already saved stop printing too — they're not deleted, they just stop showing until you turn it back on.
- Bank transfer reference. If a customer pays by bank transfer, the reference on the invoice is still your invoice number, not the PO. That's deliberate — it's what lets Mucka match the payment to the right invoice.
- PO won't save. POs can be up to 50 characters and take letters, numbers, spaces and
-/_.#. Anything else gets rejected, which usually means something's been pasted in with stray punctuation. - Wrong PO on a sent invoice. You can still edit the PO number after sending, but the copy your customer already has won't update. Send it again so their paperwork matches yours.