There are two different ways to deploy eM Client and activate the license automatically:

1.        Deployment via Command Prompt

If the goal is to simply install eM Client and load the license, use the following command in Command Prompt: MailClient.exe /activate {insert activation key here}

Similarly, you can easily deactivate eM Client license by using: MailClient.exe /deactivate

2.        Automatic deployment

If a bit more complex setup is required, you can use our "Automatic deployment process" which allows you to push various sets of settings along with the license key too. Find more detailed instructions here. 

Read more in our blogs: eM Client Server Settings & Advanced Startup