CRM system suggestion with forms that have on screen signature field.

Hello!

My family has a small business that do installation and service for airconditioners. In the last year the business has expanded to to other cities and lately it has become difficult for my old school parents to organize customers with their products and serviceman. Currently they are using google calendars with shared calendars for our service man, which worked perfectly for a small scale day to day events.

As of now there are many CRM systems that has almost everything we need like clients lists, appointment calendars for each of our serviceman etc. But the most important feature that is missing is a way for our serviceman to present a form on their mobile phone with list of tasks that are done by them to our customer, and for the customer to sign on screen to confirm.

Do you have any suggestions for a such CRM system that has such features? Or maybe an integration with such features?

Thank you!