You can remove a domain in Plesk by following this tutorial.

1. Log in to your Plesk account.

2. Click on Websites & Domains from the Sidebar Menu.
How to Remove a Domain in Plesk - 2024

3. Under the list of domains, click on the More icon How to Remove a Domain in Plesk - 2024 in front of the domain and select Remove website.
How to Remove a Domain in Plesk - 2024

4. Confirm with Yes to remove the domain.