whats the difference between all the three forms of learning/training provided

On Microsoft Learn, the three main training content types are:

• Unit: a single web page of training content. Units are parts of a module and are not standalone trainings.
• Module: a standalone, self-paced web-based training course made up of multiple units. Modules are usually small and focused on one skill or technology.
• Learning path: a collection of related modules presented in a specific order to build a broader skill.

If “session” was the term seen, the closest documented term here is unit for self-paced training, or course for instructor-led training:

• Course: a synchronous, instructor-led training presented by an instructor.

So the simplest distinction is:

• Unit = one lesson page
• Module = several units combined into one self-paced course
• Learning path = several modules combined into a broader sequence
• Course = live instructor-led training

• Microsoft Learn content and resource types
• Microsoft Learn - Microsoft Q&A