php – mysqli_query () waits for at least 2 parameters, 1 given

Warning: mysqli_query () expects at least 2 parameters, 1 given in C: xampp htdocs kios login_act.php on line 7

Warning: mysqli_error () expects exactly 1 parameter, 0 given in C: xampp htdocs kios login_act.php on line 7

those who appeared when I was about to connect to my application … I guess
my code is this