Pseudocode, are there any tools for describing the average size of projects on it?

Question

OOP

There is a medium-sized project, so far only in business processes. Tell me, in what form and with what tools can you try to describe its logic at the class/method level? Interested in something quite common, with all sorts of tasty things, if possible, free. A project with a visual part, with a backend and an API. For the internal needs of the company. Will be written in PHP/JQuery (no longer required).
Actually, what options do I see now: it’s either just writing in Russian, sort of like code with classes and all that, or just take PHP and do the same on it, but with stubs / comments / TODO in places where it’s not required at the moment the code.

Answer 1

Well, the most common is UML diagrams.
You can also see JetBrains MPS

Answer 2

I like the StateFlow control logic (not free, but you can draw not in Matlab, but at least on a piece of paper).