Services can be added or removed by first going to the Manage page by clicking the gear icon on the left of the top navigation bar and choosing Manage your account. From there, click the Update the services you offer your customers link.
On the Manage your services page you can add new services or remove existing ones. To add a new service, click Add another service. In the new box that's added, type in the name of the new service.
If you want to remove a service, click X button to the right of the service. Services that have already been selected for a job aren't able to be deleted. If you want to update a service's name/description, click the service's input box and type in any changes.
When you're finished, press Save changes to update your services.