Open apache jmeter installed folder you can find lib folder past the jar files in to lib folder

eg:- apache-jmeter-2.13\lib\

log.info("Welcome");

log.info("\n\nName : "+ vars.get("title") );

jMeter Variables are similar to properties , but they are local to a single thread

String name = vars.get("myname"); // get ${myname} variable value from input(it may be csv input, user defined variable, etc)

log.info("\n\nName : "+ name  );

String title = name + " Welcome";

log.info("\n\ntitle  : "+ title   );
 
vars.put("title", title); // put new value into ${title} variable

log.info("\n\ntitle from vars  : "+ vars.get("title") );

In properties

${title}

ref: https://jmeter.apache.org/api/org/apache/jmeter/threads/JMeterVariables.html

For removing existing header

sampler.getHeaderManager().removeHeaderNamed("Authorization");

For Adding new header

sampler.getHeaderManager().add(new Header("Authorization",Authorization ));

${__urlencode(${token})}

In Bean Shell

import java.net.URLEncoder; 

URLEncoder.encode(data,System.getProperty("file.encoding"));