My wife's the computer guru, so I'll just describe my homemade form.
I have a standard sheet of paper printed sideways. Duplicate info on each half of the sheet. I fill out both halves, keep one for me and leave one for the receipt.
Top is my info with the price of application. Then customer info, date of app, time of app, area treated and tech's name (me).
Below that is a short explanation of the app in common terms.
Then I have a fertilizer heading with check boxes next to what I use this time of year and another next to "other" in case i'm using starter or organic or something.
Below that I have a control product heading with check boxes next to my chemicals and another "other" box.
Then I have little print telling them to call me with questions, keep the kids off the lawn for an hour, remoive flag after a day.
Then at the very bottom, I have the customer's name again, and amount due. They tear off that little thing and send it back with the check, the top is for their records.
It's an exact duplicate on the other half of the sheet and I tear that off for my records and fill it out too.
That was my homemade solution that I think meets all the requirements and seems to be working okay so far. Hope that helps.