[Google Pixel 7 Pro] simplepinoi177:
P.S. Actually, looking back at this thread, I retreaded on everything discussed. I apologize for the redundant and repeat of information. I only vaguely recalled the thread and only went off of what I initially remembered from your first posts and not how the thread developed. I just saw your latest post and went off of those two things in my head. Sorry.

Ohh! Yes, that! Now I know what you mean...

This is normal behavior. It is like that on my phone. The star, or "*" as you called it, are just contacts that are your "favorites". If/when you have more contacts that are "favorites", you will see there will be a "duplicate" entry at the top of the phonebook/contact-list. This is done on purpose. When you have like 500+ contacts like me all with different various first letters in their first name (I have mine sorted by first name, others can be different), getting to those contacts can take a bit. If you/one wasn't willing to scroll and/or search for the contact, some might find it beneficial that certain contacts ("favorites" if you will) be at the very top of the contact list. I manually used to do this on my dumbphones and would do like aMichael, aChristine, aMom, aDad, just to get my most important favorited contacts at the top of the phonebook/contact list. Also, your Emergency Contacts will also be automatically put at the top in your favorites as well IIRC (If I Recall Correctly).

When you described the M with a circle and a star that was green, I pictured something different -- like a small icon or something inside of the contact thumbnail. The "M" is just Android/Google's default thumbnail for contacts that have no special thumbnail (You can actually customized them to not merely be a letter. I have pictures made for certain of my contacts; sometimes some contacts can get their Google thumbnail to be automatically uploaded into others' devices for them) and they just put the first letter of the first/last name within a circle -- I believe since yours is under "My Voicemail", it considered "My" as the first name (or first part of the name) and just added the "M". If it was entered as "Voicemail", it would've been a "V" in a circle. While green might be of significance in other instances in the Android OS (especially depending on color theme and/or the fact that Android started out as that color predominantly), in this case, it's as I just stated and it's only that color because that seems to be the color theme of your phone.

As for why it's automatically already entered in your phonebook/contact-list; there are a couple of possibilities. Your carrier might've been able to do that automatically -- although in the case of Verizon, they automatically add their dialpad codes like #PMT (for making payment) or #BAL (to check balance) in the contact list than "My Voicemail". In most cases, it's unnecessary as most US devices are set up to merely hold the #1 key to get to your carrier's voicemail. I do recall Verizon also has a dialpad shortcut of *86 to get to voicemail as well; or at least they used to. It's been a while, I've changed to YouMail and then to Google Voice for my voicemail needs....

In any case, this might explain why, in my case, putting the number *86 in my contacts might automatically be identified as "My Voicemail" or "Voicemail" and, depending on the carrier, may have it automatically set as a "favorite".

It depends on what you have your System Navigation set as; 3-button navigation (Back, Home, and App Switcher button), 2-button (a Home and Back button), or Gesture navigation. In 3-button, there's an actual button you can tap to activate. In 2-button & Gesture, you swipe up and hold at the Home button (or Home "bar" in Gesture navigation).

Hope all this helps. If I spoke rather plainly, I apologize if it was received as too obvious & simplistic; I know that you are new to smartphones and didn't know how far your experience and learning has come so I rather spoke from the bottom up to "cover all the bases"....