click() that you invoke on located element does not return anything. It is void (you probably used this "type" in some of your methods declaration like
public static void main(), etc).
So as that method is called the last in your right-hand side of assignment, Java assumes you're trying to assign what the method returns to what you have on left-hand side.
Hence, type mismatch occurs.
The proper approach would be first assign an element (here it wouldn't be any issue since
findElement() is called last on the right-hand and it returns
WebElement uploadElement = driver.findElement("//input[@id='HorizontalLogoPath']");
and then invoke
click() of your