Enabling Clean URLs
First, to enable the Clean URLs feature of Drupal, follow the given steps:
1. Access the admin dashboard of your Drupal site.
2. Click on the Configurationlink on the admin navigation menu at the top of the page.
3. Find the section named Search and Metadata, and then select the option Clean URLs.
4. If your server and installation are able to run Clean URLs, you should see the screen shown in the following screenshot. If you see this, simply click on the Enable clean URLscheckbox
5. Click on the Save configurationbutton and you should be greeted by a confirmation dialogue.
If there is an issue blocking the use of Clean URLs, you will not see the previous screen, but rather a different dialogue, informing you that there is a problem and directing you to an online help file. That screen will also contain a button labeled Run the clean URL test. You can click on that button to confirm whether there is a problem. If the issue remains, it is likely that your server is not set up to permit the use of Clean URLs and you will need to read the online help files and possibly also contact your webhost or server administrator.
Another possible problem, though very rare, is that the .htaccessfile included with your Drupal installation is missing or flawed. By default, Drupal comes with a .htaccessfile; it should be located in the root of the installation. Check your site to make sure it is there and that is has not been modified in such a fashion as to defeat its ability to function properly