A Jedi was a Force-sensitive individual, generally a member of the Jedi Order, who utilized the mystical energies of the light side of the Force.
In the world of Star Wars, the Jedi fought to maintain peace and establish justice in the Galactic Republic, having as enemies the Sith who, on the other hand, had an affinity for the dark side of the Force.
Within the Jedi Order there were four ranks that followed a pyramid scheme, they are the Youngling or Jedi Initiate, Jedi Padawan, Jedi Knight and Jedi Master (via Fandom).
Youngling / Jedi Initiate
They were Force-sensitive children beginning in the Jedi arts. From a very young age they were detected, taken away from their homes and assigned to a clan to receive appropriate training.
During the era of the Galactic Republic these initiates spent most of their time in the Jedi Temple, where a Jedi Knight or Master could choose one to become their apprentice (Padawan). If a child reached 13 years of age and was not chosen, they were assigned a role in the Jedi Service Corps according to the specialty they were studying.
In the New Jedi Order, children, adolescents and adults were accepted into the group of initiates, and unlike what happened before, if they were sent on missions away from the academy being supervised by Jedi with more experience.
Padawan were Force-sensitive teenagers trained by the Jedi Order to become Jedi. They were first trained in classrooms with other students, and by reaching a certain age they were apprenticed to a Jedi Knight or Jedi Master to receive training individually. These Padawans used to go on missions with their teachers.
At first the Jedi Knights or Jedi Masters chose their apprentice, and by the way they could only have one at a time, but during the Clone Wars the Jedi Council began to assign Padawan to the Jedi.
One detail of this range is that most Padawans grew a distinctive braid.
Following the pyramid are the Jedi Knights, who are members of the Jedi Order who completed their training at an academy, were guided as Padawan, and conducted Jedi tests. As a Knight and members of the Order, they received assignments directly from the Jedi Council.
Finally the highest rank a Jedi could achieve, the Jedi Master. A title bestowed upon individuals who demonstrated devotion and great skill in the Force, and was generally reserved for Knights who succeeded in turning multiple Padawan into Knights, as well as someone who performed extraordinary deeds.
It should be noted that being a Jedi Master was a requirement to be able to be part of the Jedi High Council, although there were some exceptions such as Anakin Skywalker who did not achieve the rank of Jedi Master but Palpatine appointed him as a member of the High Council.
All these ranks were based on three fundamental principles that are the Force, knowledge and self-discipline, basic elements in the life of a Jedi.
If you are interested in the opposite side, in this link you can find out the ranks of the Sith order.