Step 1: Go to the installation directory of Tomcat, then into conf folder, the default installation directory is: C:\Program Files\Apache Software Foundation\Tomcat 8.5\conf
Step 2: Open server.xml file using any text editor
Step 3: Change the following line with a new port number
Step 4: Open command prompt, and navigate to Tomcat bin directory, enter command “startup.bat” to start the server
Step 5: Open web browser and open “localhost:PortNumber”, in my case it is: http://localhost:9090/
If you are able to see Tomcat page them your installation is successful.