What is the correct name for this competence (Who is it)?

Question

User interface

Hello
, I would like to learn/become more competent in designing interfaces based on user data , i.e. design interfaces:
- well-developed logical
- so that the user can quickly get the desired result from the system
Please tell me what is the correct name of this area / competence?
1. At this stage, I am not interested in competencies related to design, incl. how to beautifully draw or implement some kind of button or function, what are the sizes of the fields. The above competencies are of particular interest.
2. What to study? What books?
Examples of the work of a specialist with this competence:
№1
Developed electronic document management system.
Example: we developed an electronic document, there were no requirements for the form, so it was made "as done". It seems that all the information is on the form, but it is not logically worked out.
During user testing, we learned that: the
user, for example, first indicates the date for which the document is generated, then usually indicates his organization, then his department - which means that these fields need to be built according to the scenario, i.e. done first. We alter the header part of the document.
No. 2
There is no software product, at the concept or development stage.
Example:
There are functional requirements for a product.
We identify users, their preferences, goals, etc.
We form user scenarios We
develop the concept of the program
Testing the concept on users
Prototype development
Testing the prototype, incl. on users
, etc.

Answer 1

User eXperience (UX) specialist.

Answer 2

UX designer. Or just a designer.

Answer 3

Previously, it was called MMI (Man-Machine Interface), then a slightly modified name HMI (Human ..) appeared. Ergonomic requirements must be taken into account.