Two ways to bring a Zoho Books, Invoice or Inventory company across. Either works; the whole backup is the faster one if your export includes everything you need.
The whole backup, in one drop
In Zoho, Settings → Data Backup → Backup Your Data, download the zip, and drop the WHOLE zip on the Pick screen. Contacts, Vendors, Items, Chart of Accounts, Invoices (with their line items), Bills (with their line items), Customer and Vendor Payments and Journals are read straight out of it. Anything in the zip Finocket does not recognise is listed by name rather than silently skipped.
Or one module at a time
Contacts → ⋮ → Export → Contacts (CSV, all columns). Items → ⋮ → Export. Accountant → Chart of Accounts → ⋮ → Export. Sales → Invoices → ⋮ → Export (Invoices, then Invoice Items). Purchases → Bills → Export. Payments Received / Made → Export. Accountant → Manual Journals → Export.
What comes across today
Parties, items, your chart of accounts with opening balances, invoices, bills, payments and journals. Contacts is on the list for a closer read next; today it comes across as a party like any other.
What is deliberately not copied
Filed GST returns, IRNs and e-way bills belong to the GST portal, not to Zoho. Bank-statement matches, reconciliations and attached files stay behind too, and so do recurring profiles, reminders and Zoho's own invoice and estimate templates: those are Zoho's presentation layer, not your figures.
After you drop the file
Same five screens as every other source: matching columns, a dry run with a verdict on every record, then Import and Reconcile. The mechanics (and how undo and re-imports work) are in Import your data from Zoho, Odoo, Vyapar or a spreadsheet. Back to the full list of sources.