The extension of your stay for studies is the procedure that you must do to continue studying in Spain every time your stay for studies expires.

That is, what is the situation that many foreign students live in?

Well, in most cases, they come to Spanish territory to study for more than 1 year (either because they are studying a degree that lasts 4, or because after finishing the degree they access a master's degree or another type of training, etc.)

The stay for studies, the authorization that allows them to stay legally in the country while said training is being completed, it is only granted for 1 year.

Therefore, if your studies last more than those 12 months, you must extend that initial authorization, and this is known as an extension of stay for studies.

In the case of having made a joint application and being in Spain with your relatives, the extension of your stay for studies will also extend the duration of that of said relatives.