We have been developing tailor-made software for decades now. Most of that time we have been focusing on web technologies. We believe software based on web technologies benefit from the farthest reach possible nowadays as there is a web browser on nearly every device in the world and most of them are complying with the majority of web standards.
We implement standards-compliant websites based on online content management systems (CMS). Our favourites have been Contao and Wordpress for quite some time now. Our websites come with responsive designs to make them look and feel perfect on desktop computers and smartphones alike.
But to be honest, we think the era of such online CMS is on the decline. In opposition to them, static site generators (SSG) have been on the rise for years now. In our opinion, they are a better fit for common websites. Using them is preparing any website to become a full-fledged web application with ease.
A web application is different from a website in that it doesn't just render content but include extended functionality that make it feel more like a regular application. In recent years, due to the improvements on web technologies and their support in browsers web applications have become a valid replacement for regular applications in the vast majority of use cases.
As mentioned before, there is a browser on nearly every platform. Desktop computers, tablets and smartphones all have sophisticated web browsers. They run on Windows, MacOS, Linux, iOS or Android. They work regardless of the type of processor.
Eventually, for all of these platforms there is a tool for wrapping a web application in a container so that it can be distributed and installed like a "regular" application. In fact, distinguishing them from each other isn't that easy anymore. Certainly, you have been working with lots of web applications already.