We need someone who knows how to use Mail Merge in Word to create an invoice. Who has experience with Mailings?

Hello everyone! We need someone who knows how to use Mail Merge in Word to create an invoice. Who has experience with Mailings? You have to use an Excel to create an invoice in Word and then convert it to PDF. The thing in general seems to be simple when talking about Mailings. There are thousands of tutorials on YouTube, but there are some difficulties with the bills. You have to create the invoices according to the example. If the customer has only one service, then everything goes great. But if the customer has several services, then they are in the Excel under each other. And the program does not understand that for example Lenka Lachmeyer is the same customer and instead of making only one invoice, the program creates several. Then we have four different bills from Lenka Lachmeyer instead of one. That is bad. We need someone who can change this problem. Thank you.