With this plugin you'll be able to export your themes in a .zip file and then install with that .zip file the same theme in other servers using the "upload" feature of wordpress.

[29-11-2011] 1.5 * Permisson problems fixed. * Warnings added. * Directory structure changed.

[04-09-2014] 2.0 * Security bug fixed * Old zip files are automatically deleted * Better session management * 100% WP 4.0 Compatible

[22-09-2018] 2.1 * Warning fixed * Language functions added

[22-09-2018] 2.1 * Typo fixed

Just paste this folder to the wp-content/plugins folder in your server and then activate it from the backend. You will found a new item in the "Appearence" menu called "Export". Besides, you can also use the WordPress repository from the dashboard to install it.