What is better with salt for password storeing?

MD5:

$hash = md5($password . $salt); 

Password_hash:

$hash = password_hash($passwod, PASSWORD_DEFAULT, $salt); 

SHA1:

$result = sha1($salt.$string); 

What is better with salt for password storage?

MD5:

$hash = md5($password . $salt); 

Password_hash:

$hash = password_hash($password, PASSWORD_DEFAULT, $salt); 

SHA1:

$result = sha1($salt.$string);