Beacuase Univision is not a premium service, so you can access the service at tv.univision.com.
If you're using a connected device, you can download the Univision app and activate it using a cable or TV subscription.
If you don't have a TV provider, consider purchasing a subscription through the Univision Now app. This will give you access to all content from Univision and UniMas Live and on-demand.