I would evaluate the different systems the company is using for various processes before deciding on something for printing receipts. Do they create POs? Do they create estimates? How do they submit invoices? How do they get paid? Who does the books? Who does the taxes?
You may find that a general software such as Quickbooks would be great. You may also find that there are programs tailored to their industry is better.
I have a metal fabrication business and use QB Contractor Pro. We create estimates. If a customer signs off on the job, we convert the estimate into an invoice. When they pay the invoice, the invoice gets a "Paid" stamp across it and it can serve as a receipt. I use it for bookkeeping as well and set up the chart of accounts to mirror what my accountant uses so all of our reports are easy for them to read and they can send me account-specific general journals to make at the end of the year to close out the books.
The job costing and profitability reports leave something to be desired as it appears you must bill the customer for your hours for your labor to appear on the reports. We don't do that - we estimate a certain number of hours and whether we go over or under, our final price doesn't change. That has been pretty disappointing but I don't know of any software that would provide as much of what we need at that price point.
That being said, my parents own a pest control business and had a lot of different needs. They purchased software specifically for pest control companies that helps them put together routes, track employee payments, etc.
I would recommend that you spend 3-6 months learning how the business currently works before trying to change the software. That will give you time to understand where technology would help the most and, therefore, which software would be the best choice for your business.
Congrats and good luck!