1. Configure Tomcat Web Management Interface:
$ vim $TOMCAT_HOME/conf/tomcat-users.xml

2. tomcat-users.xml file :
<tomcat-users>
    <user username="admin" password="password" roles="manager-gui,admin-gui"/>
</tomcat-users>

3. By default, newer versions of Tomcat restrict access to the Manager and
Host Manager apps to connections coming from the server itself. Since we are
installing on a remote machine, you will probably want to remove or alter this
restriction. To change the IP address restrictions on these,
open the appropriate context.xml files.

$ sudo vim $TOMCAT_HOME/webapps/manager/META-INF/context.xml
$ sudo vim $TOMCAT_HOME/webapps/host-manager/META-INF/context.xml

Inside, comment out the IP address restriction to allow connections from anywhere.
Alternatively, if you would like to allow access only to connections coming from
your own IP address, you can add your public IP address to the list:

<Context antiResourceLocking="false" privileged="true" >
  <!--<Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />-->
</Context>

system restart tomcat