Whilst I am not in business I found FormConnect Pro really great for setting up forms (I wanted something that I could use to create a checklist for house-hunting when viewing properties.
I created a multi-page form that I could instantly add camera pics to, a series of check boxes for use as an aide-memoire and several fields I could complete with text or simply complete with a signature.
The Pro version also lets you create invoices and can calculate totals for you.
If I was a Plumber I could see me using it for ...
1. Creating a Customer Enquiry Sheet
2. Collating data such as photos of the problem in a Fault Sheet as proof for customers
3. Creating an Estimate
4. Using. a Job Sheet to record work done (this could be a tick list to include safety checks), record parts used/hours worked etc and, again photographic evidence of condition the job was left in
5. Creating invoices
All of the above could include your logo and can be completed on-site on your IPad. Certainly worth a peek ....
https://itunes.apple.com/gb/app/formconnect-pro/id590313779?mt=8
Below are a couple of screen grabs from a couple of different pages from my Form ..... doddle to create them. If I can do it, anyone can!!!!!