Web development involves creating websites and applications specifically for use online, software development involves building applications that may or may not be for online.
Web development includes creating websites for computers or mobile devices, front-end and back-end development, and optimal UX design. These are all accessed through online platforms that work from a server or online database.
Software development can include applications developed for online use, but it is not restricted to online only. The software can work as an on-premises application, used as a standalone solution, or as part of a network – all without ever being online.
There is some overlap between the two disciplines. When you are in the market for either a web developer or a software developer, you must understand the difference between them.