1. In the Plesk control panel of the website click on the "Websites & Domains" tab and click on the "Show Advanced Operations" link to expand the the Advanced Operations section there.
2. Now click on the "Java Applications" link from the Advanced Operations section.
3. This will open the Java Applications module from where click on the "Install Java Application" Icon.
4. Now Add New Java Application module will shown and click on the "Browse" button there to select the desired .war file. Then click "Ok" to deploy that application on Tomcat Apache. Please note that the file name of the .war file will be used as the uploaded application's name and it will available at http://site_url/application_name location.