How to set "value" to input web element using selenium?

driver.findElement(By.id("invoice_supplier_id")).setAttribute("value", "your value");

Use findElement instead of findElements

driver.findElement(By.xpath("//input[@id='invoice_supplier_id'])).sendKeys("your value");

OR

driver.findElement(By.id("invoice_supplier_id")).sendKeys("value", "your value");

OR using JavascriptExecutor

WebElement element = driver.findElement(By.xpath("enter the xpath here")); // you can use any locator
 JavascriptExecutor jse = (JavascriptExecutor)driver;
 jse.executeScript("arguments[0].value='enter the value here';", element);

OR

(JavascriptExecutor) driver.executeScript("document.evaluate(xpathExpresion, document, null, 9, null).singleNodeValue.innerHTML="+ DesiredText);

OR (in javascript)

driver.findElement(By.xpath("//input[@id='invoice_supplier_id'])).setAttribute("value", "your value")

Hope it will help you :)

As Shubham Jain stated, this is working to me: driver.findElement(By.id("invoice_supplier_id")).sendKeys("value"‌​, "new value");