To install a module in Drupal 7, copy and uncompress it in the installdir/apps/drupal/htdocs/modules folder. Then, enable the module in the “Modules” section of the Drupal administration panel.
To install a module in Drupal 8, follow these steps:
Locate and filter the module you want to install. Find a list of available modules at the Drupal module directory.
Download it to your local computer.
Use the filter options in order to find the module. Once you find it, click on the module name to see the details. Select the version and the file format. Here’s an example.
Visit your site and log into your Drupal 8 admin interface. In the Administration menu navigate to the “Extend” tab. Click the “+Install new module” button.
Browse to the downloaded file and select it. Click the “Install” button to complete the installation.
Once the installation is complete a popup window shows a confirmation message:
Return to the modules list in the “Extend” page and locate your module. Enable it and click the “Install” button.