If it is a plugin you just SFTP (see Filezilla) from the one site to another. Let’s say local host to Web Server. The plugins are in the dir /wp-content/plugins/<my plugin>, just FTP to the Destination, then enter to the Dashbord of Destination Plugin and Activate & Configure.
Another way is with Git, you local installation is needed to update your Wen inststallation , as two Git repositories. Transfer what is needed, NOT TRASFER wp-config.php that includes passwords.
