Creating a plugin or app

I’ve done a little reading on creating an app but I don’t see anything on creating an environment. Can Visual Studio be used for this or maybe eclipse. Is it basically a website project?

Never mind, my found the tutorial inside the documentation. I should probably start there. https://docs.nextcloud.com/server/12.0/developer_manual/app/index.html

What I’m looking for is a couple of editable documents. For my small business I’d like to be able to have service techs in the field be able to fill out an electronic form / service ticket with the amount of time they spent, customer name, date, description, parts used etc. and capture an electronic signature from the customer. Then push a button and have the form sent to accounts receivable email or shared folder for billing. Also a weekly time sheet would be nice. Don’t know if some thing like this exists already or can be accomplished using PDF’s or something.

Anybody doing something like this now?