1. Login to your DirectAdmin Account.
2. In the Account Manager section, click on the Subdomain Management Icon or type Subdomain in the navigation filter box and then the option will appear. Click on it. 
3. In the** top right-hand side**, click on the Add Subdomain button. 
4. Under Subdomain Enter your subdomain name you wish to create.
5. Click on the Add Subdomain button. 
Your subdomain will be created.