non functional requirements

powerbiexpert22 

Functional requirements are like a checklist for a system as they specify what the system must do.  If these requirements aren't met, your software won't function properly.

Non-functional requirements say how the system/software should work and be built. Non-functional requirements determine exactly how the system should operate: its speed, what's going on behind the scenes, and so on

• Functional requirements are essential; the system can’t run unless these are met.

• Non-functional requirements, on the other hand, aren't mandatory; the system can still work even if these aren't fully met.

   

  https://www.ironhack.com/gb/blog/functional-vs-non-functional-requirements-understanding-the-core-differences-and

   

  https://www.altexsoft.com/blog/functional-and-non-functional-requirements-specification-and-types/

   

  Phil