Levels are defined by 'can-do' descriptors.
Definition-
The CEFR categorises language proficiency into six levels, A1–C2, which can be further subdivided based on the needs of the local context. The levels did not appear out of nowhere in 2001, but rather evolved over time, as described below.
Types-
Conclusion-
Based on these accomplishments, the CEFR has developed a description of the process of mastering an unknown language by type of competence and sub-competence, using descriptors for each competence or sub-competence, which we will not go into further detail here. These descriptors were developed without regard for any particular language, ensuring their relevance and universal applicability. The descriptors describe each skill's progressive mastery, which is graded on a six-level scale (A1, A2, B1, B2, C1, C2). For further information you can visit SpeakoClub and improve your knowledge about CEFR.