Assuming your exported data arrives in Excel format in tidy shaped table (not as comma delimited etc) with a row for each “hire event” that you want to invoice then
1. Create yourself a suitable invoice template on another worksheet in the same excel workbook. Add in VAT calculations, charging tariff etc so that it will compute the cost for the hire event.
2. Link the cells in the template to the relevant data in the first row of your data table using =cell address type command.
3. Your invoice form will now be completed with your first hire event.
4. Save as pdf the invoice worksheet for hire event #1
5. Delete row 1 of your data table and the invoice form will now be updated with the row 2 data.
6. Update the invoice number and any other manual data needed
7. Save as pdf the invoice worksheet for hire event #2 etc.
If you don’t want to delete the row then cut and paste it into a “completed invoice” worksheet. You could then add a column to enter the invoice number you used for that row.
There is undoubtedly a way of doing all that automatically but I’m not that bright
