I'm trying to setup my business address to take payments via invoice and it will only let me put in an address for America. I'm in the UK though

Make sure you are opening QBO UK version, not US version. Login to your existing account as Primary Admin and navigate to Billing and Subscription menu. If you are paying the subscription not in GBP, it is highly possible you are not using QBO UK version.

https://quickbooks.grsm.io/UK

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