Typical AvaTax for Accounts Payable workflow

After a quote is entered onto your site, call the CreateTransaction API with type set to PurchaseOrder. This will get you a tax calculation based on the shipping and destination addresses, but it won't record a permanent transaction. No cleanup is required for abandoned carts.
Review the invoice entry, then call CreateTransaction again with type set to PurchaseInvoice. Set the taxOverride type to VendorChargedTax, and set commit to false. This won't record a permanent transaction.
In the response, review the use tax accrual (if any) and the AP status field. Based on your review, determine whether to accrue use tax in the ERP or accrue use tax in the Avalara Portal.

Accrue use tax in the ERP

Call CreateTransaction again with type set to PurchaseInvoice. Set the taxOverride type to VendorChargedTax, and set commit to true
In the response, review the document status, totalTax (for the accrual amount), totalTaxCalculated (for the Avalara-calculated tax), VarianceCalculatedForDocument, apStatusCode, and apStatusCode.
Complete any additional GL entries/invoice tax amount adjustments as needed.

Path 1:

Download the transactions accrued in the Avalara Portal.
Review the document status, totalTax (for the accrual amount), totalTaxCalculated (for the Avalara-calculated tax), VarianceCalculatedForDocument, apStatusCode, and apStatusCode.
Review your policy for posting to the General Ledger, then post the transaction.

Path2:

Asynchronously fetch the document from Avalara.
Review the document status, totalTax (for the accrual amount), totalTaxCalculated (for the Avalara-calculated tax), VarianceCalculatedForDocument, apStatusCode, and apStatusCode.
Post adjustment for GL entries for use tax accrual in the ERP.