waitforelementpresent(locator.login_email);
    click(locator.login_email);
    type(locator.login_email,email);
    click(locator.login_password);
    type(locator.login_password,password);
    Thread.sleep(5000);
    click(locator.login_button); //This button I need to click

public static void click(By by) {
    WebDriverWait wait = new WebDriverWait(driver, defaultWaitPeriod);

    wait.until(ExpectedConditions.elementToBeClickable(by));
    driver.findElement(by).click();
}

    public static void type(By by, String type) {
    WebDriverWait wait = new WebDriverWait(driver, defaultWaitPeriod);

    wait.until(ExpectedConditions.visibilityOfElementLocated(by));
    driver.findElement(by).clear();
    driver.findElement(by).sendKeys(type);

public By login_email=By.xpath("//input[@placeholder='Email ']");
public By login_password=By.xpath("//input[@placeholder='Password ']");
public By login_button=By.xpath("//form[@class='m-t  ng-dirty ng-valid-email ng-valid-parse ng-valid ng-valid-required']//button");