I Use Elementor with a Localhost, Can the License be Transferred to the Real Server?

When you use Elementor with a localhost, it is not considered as an activation. 

To activate Elementor Pro to a live site, you can do it either via your WP dashboard with your license key or within your account in your Elementor account. 

If you opt for the second option, go to  Purchases > View licenses > Manage sites and then you add the URL of the live site next to the Add Site button.