The Scenario
You are an account manager at a digital agency. It is the 28th of the month and every billing milestone invoice must go out before the 30th.
Twelve projects hit their billing milestones this month. You have an Excel workbook — the Billing Milestones tab — with client ID in column A, project ID in column B, invoice amount in column C, and due date in column D. Twelve rows, all confirmed by finance.
Creating invoices in Harvest one by one means logging in, selecting the client, creating the invoice, adding the line item, setting the due date, saving, and moving to the next row. At four minutes per invoice, twelve invoices is nearly an hour. And if you make an error on invoice six, you find out when the client calls about the wrong amount.
The bad version of Tuesday morning:
- Open Harvest, find the first client
- Create invoice, add line item amount, set due date, save
- Note the invoice ID in your notebook because there is nowhere else to put it
- Repeat eleven times
- Discover invoice nine went to the wrong client because you clicked too fast
- The 30th is tomorrow.
The fast version is one prompt.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent inside your Excel workbook that reads the billing milestones table and creates every invoice in Harvest in one pass.
Open the SheetXAI sidebar and type:
For each row in my Billing Milestones tab, create a Harvest invoice using the client ID in column A, amount in column B, and due date in column C — write the returned invoice ID into column D.
SheetXAI reads all twelve rows, creates each invoice in Harvest with the right client, amount, and due date, and writes each invoice ID back into column D. When finance asks for the invoice numbers, the workbook already has them.
What You Get
Twelve Harvest invoices created with:
- Correct client assignment — from column A, no click-through required
- Correct amount — from column B, no manual line item entry
- Correct due date — from column C, no date-picker errors
- Invoice ID in column D — written back automatically for tracking
The IDs in column D close the loop. Finance can look up any invoice directly in Harvest by ID, or you can use those IDs in a later prompt to pull payment status and flag overdue invoices.
Need a custom line item description per invoice? Tell SheetXAI which column has the description and it includes it in the line item.
What If the Data Is Not Quite Ready
Invoice workbooks are almost never perfectly clean before the billing run. SheetXAI handles the data problems and the invoice creation in one prompt.
When due dates are in a text format Harvest does not accept
Your finance team entered due dates as "June 30" instead of "2026-06-30" and Harvest expects ISO 8601 format.
For each row, convert the due date in column C from "Month DD" format to YYYY-MM-DD format. Then create a Harvest invoice using the client ID in column A, amount in column B, and the converted due date. Write the invoice ID into column D.
When some rows are marked as on hold
Column E has a status field and three rows say "On Hold." You want to skip those and only create invoices for rows marked "Ready."
Filter to rows where column E says "Ready." For each of those rows, create a Harvest invoice using columns A, B, and C. Write the invoice ID into column D and skip any row where column E is not "Ready."
When you also need to pull outstanding unpaid invoices to cross-reference
Before creating the new invoices, you want to know which clients already have unpaid invoices outstanding so finance can flag them.
First, pull all unpaid Harvest invoices that are more than 30 days past due. List them in a new tab called "Overdue" with client name, invoice number, amount due, and days overdue. Then return to the Billing Milestones tab and create invoices for every row where column E says "Ready."
When invoice amounts need to come from a formula rather than a fixed value
Some rows in the workbook have hours in column B and rate in column C, and the invoice amount should be hours × rate, not a pre-calculated total.
For each row, calculate the invoice amount as column B × column C and write it into column D. Then create a Harvest invoice for each row using the client ID in column A, the calculated amount from column D, and the due date in column E. Write the returned invoice ID into column F.
The pattern: describe what the invoice should contain and where the numbers live. SheetXAI handles the Harvest API calls and the ID writeback so you have a complete audit trail in the workbook.
Try It
Get the 7-day free trial of SheetXAI and open your billing milestones workbook, then ask it to create all the invoices before the 30th. The Harvest integration is included in every SheetXAI plan. For AR follow-up, see how to pull Harvest payment records into an Excel workbook or the Harvest in Excel overview.