To enable HTTPS support for Tomcat, you need to edit the configuration file server.xml.

1. Open the server.xml file in a text editor. You can find this file in /path/to/tomcat/conf/server.xml.

2. Find the following lines:

   <Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol" maxThreads="150" SSLEnabled="true">
          <SSLHostConfig>
              <Certificate certificateKeystoreFile="conf/localhost-rsa.jks"
                           type="RSA" ></Certificate>
          </SSLHostConfig>
      </Connector>

   If the block is commented out, uncomment it.

3. Edit the configuration and add your port and certificates, for example:

   <Connector port="443" protocol="HTTP/1.1" maxThreads="150" SSLEnabled="true" URIEncoding="UTF-8" maxHttpHeaderSize="65536" maxPostSize="1100715200">
      <SSLHostConfig hostName="XX.XXXX.XX">
          <Certificate certificateKeyFile="conf/private.key"
                       certificateFile="conf/zertifikat.crt"
                       certificateChainFile="conf/CHAIN.pem"
                       type="RSA" ></Certificate>
      </SSLHostConfig>
   </Connector>

   For more information on the SSLHostConfig property, see https://tomcat.apache.org/tomcat-8.5-doc/config/http.html#SSL_Support_-_SSLHostConfig 

   Below you can find a summary of the most important options:

   Attribut	Wert	Beschreibung
   port	443 (default)	Port for the HTTPS connection.
   URIEncoding	UTF-8	UTF-8 should be used, as it is also used by FORMCYCLE.
   maxHttpHeaderSize	65536	This value should not be changed.
   maxPostSize	1100715200	Maximum size in bytes for POST requests. This applies, for example, when a form is submitted and includes file uploads. 1100715200 means 1 GB.
   hostName	*	Name or IP address of the host.
   certificateKeyFile	*.key	The private key of the certificate.
   certificateFile	*.crt	The certificate file.
   certificateChainFile	*.*	The certificate of the certificate authority (CA), if required.

Further possibilities to configure a certificate in the Tomcat at the connector:

Integration via KeyStore:

If you have a KeyPair file (*.pfx, *.p12) you can also include it directly: