Opencv2/opencv.hpp: No such file or directory

I try to use c++ with opencv for the first time.I read various tutorial like those one:
for vscode
on Linux
in terminal
But it’s still the same debuting error(he don’t find opencv):

,,main.cpp:2:10: fatal error: opencv2/opencv.hpp: No such file or directory
    2 | #include <opencv2/opencv.hpp>
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.

Thanks for your help.