Are there any invoicing systems that integrate with our accounting system and handle multi-office billing workflows?

Yes — there are plenty of invoicing/billing systems that integrate with common accounting platforms and support multi-office or multi-entity workflows.

A few good categories to look at:

1. Invoicing/AP automation tools with accounting integrations

These typically sync invoices, customers, tax codes, payments, and journal entries into systems like QuickBooks, Xero, NetSuite, Sage, and others.

Examples:

• Bill.com — strong for approvals, AP/AR, and accounting sync
• Melio — simpler payment + invoicing workflows, often used with QuickBooks
• AvidXchange — more enterprise AP/AR automation
• Tipalti — strong for multi-entity, global payments, approvals
• Ramp Bill Pay — good if you also want spend management

2. Accounting-platform native invoicing modules

If you want fewer integrations and tighter sync, many accounting systems have built-in invoicing or billing:

• QuickBooks Online Advanced
• Xero + add-ons
• NetSuite SuiteBilling
• Sage Intacct
• Zoho Books

3. Multi-office / multi-location workflow tools

If your challenge is routing invoices by office, location, department, or cost center, look for:

• approval routing by office or entity
• separate GL mappings per office
• role-based permissions by location
• consolidated reporting across offices
• support for multiple tax jurisdictions

Commonly used for this:

• Tipalti
• Bill.com
• NetSuite
• Sage Intacct
• Odoo (if you want more customization)

What to verify before choosing

To make sure it fits your accounting system and workflow, check:

• Does it integrate natively or via API?
• Does it support multi-office / multi-entity billing?
• Can invoices be routed to the correct office for approval?
• Can it sync customers, vendors, classes, locations, departments, and projects?
• Does it support your billing model: recurring, milestone, usage-based, or one-time?
• Does it handle tax/VAT/GST across offices or countries?

If you tell me:

1. your accounting system,
2. how many offices/entities you have,
3. whether you need AP, AR, or both,
4. and whether you bill clients or pay vendors,

I can recommend a short list of best-fit options.