We were recommended to read the book Microcopy
UX Writing is the practice of crafting the words that appear in user interfaces—like buttons, error messages, navigation menus, and instructions. It focuses on creating clear, concise, and helpful text that guides users through a product or service.
The goal is to make interactions intuitive and reduce friction by using language that's easy to understand and action-oriented. Good UX writing helps users accomplish their goals quickly and confidently.
So it is using words rather than pixels to convey a message to a user e.g a loading bar needs the word loading below it to understand it

Simple language means using clear, straightforward words that users can easily understand without confusion or ambiguity. It involves:
People understand simple language rather than complex language, the simpler the language the easier it is to understand without much focus.
Explain the action to a 4 year old, it’s not about dumbing down, it’s about opening up
For example, instead of "authenticate credentials," you'd write "sign in." Instead of "terminate session," you'd write "log out." The goal is to make the interface accessible and easy to navigate for all users, regardless of their technical expertise.
Formatting refers to how text and content are visually structured and presented in a user interface.
Formatting helps users understand the UI in several key ways: