Google cloud app sign form upload picture.

We are a small it company specialist in offering computer services to our customers, we use g suite as part of our sales and tech procedures. We need a app fully integrated in g suite and Google cloud services, that alouds us to desing a form in Google and add it a function for our customers to sign handwriting, and then upload pictures taken by the device. Google cloud platform development is mandatory as our organization's main ofimatic structure is gsuite based. We already use Google forms and sheets for almost everything and don't want this to change. We will provide a fress gsuite basic environment with one account, but can negotiate to upgrade it to business with more accounts if the project needs so. Part of the job is have a we'll documentated project, so we can replicate the works in o own domain, this has to be done by our engineers ( they are not specialist in app development, but uses to work with g suite web hosting and Joomla, so are not complete noobs in this matters) We prefer that the app runs standalone, none installed in the phone, just browser, in both desktop and mobile devices