Looking to start developing software. Would users of a VB program need to have .NET installed? Being a Chromebook user, I have often been confronted with this.

This is a forum about Notepad++. We aren’t experts in all possible programming languages, and this isn’t the place for generic programming questions. (The answer to that question is the same whether you are using Notepad++, notepad.exe, VSCode, or copy con to create your source code, hence it’s off-topic for a Notepad++ forum.)

Also, does Assembly in N++ refer to x86?

It refers to essentially any assembly language. My guess is that x86 assembly would have all its common keywords included in the various keyword lists, but all assembly languages that I’ve ever heard of have essentially the same structure, so can be parsed using the same rules. If there are keywords you feel are missing for your desired Assembly, the various INSTRUCTION and DIRECTIVE styles for Assembly have User-defined keyword lists that you can add more keywords that are specific to your flavor of Assembly.