You can’t just import accounts receivable from one business into another.
Edit: But you can export “Customers” from one business and “Batch Create” into another but you need to create a Test Customer first before you can see the “Batch” buttons
Accounts receivable are unique to the business which is owed money by the customer.
If you were referring to accessing business records from another installation of Manager, rather than in another business, you do that by importing backups. There are many threads about this on the forum. The basic Guides are here: