From UI:
Tool-->Generate HTML report
From Command-line:
Generation from an existing sample CSV log file:
jmeter -g <log file> -o <Path to output folder>
Generation after load test:
jmeter -n -t <test JMX file> -l <test log file> -e -o <Path to output folder>
https://jmeter.apache.org/usermanual/generating-dashboard.html