If you would like to filter out Kixie voicemail/SMS notifications (or this can be applicable to any emails you would like to filter out of your mailbox), you can do so in a few simple steps on Gmail.
1. To filter out Kixie notifications, you will be filtering them out by email address. To filter by the sender's email address, open the email that you want to filter out and click on the three dots above the email and click "Filter messages like these."
2. Gmail will automatically populate the sender's email you were viewing into the "from" category. That way you will filter out all e-mails from that sender. In my example, I'm using firstname.lastname@example.org which is where the automatic voicemail notifications are sent from.
Now click "Create Filter."
3. On the next screen, select "Skip the inbox (archive it)" and "Apply the label" in order to filter these voicemail emails into a separate folder that coordinates with the label you create for it.
4. You can create a new label (for example: Kixie voicemails) or use an existing label.
Now any emails you receive from that sender's email address will automatically be labelled into another folder, bypassing your inbox to reduce clutter!