I just re-watched the introduction of the first iPhone, and one thing that stood out to me was this "visual voicemail" thing they showed. To this day I still just get an SMS if someone leaves a message, and then have to call my voicemail and listen to recordings one by one. That's still the norm for standard phone contracts here afaik, it's ridiculous!
Now my iPhone, actually transcribes my voicemail live and gives me the opportunity to pick up during them leaving the voicemail. Like old-school answering machines used to do.
Seems to heavily depend on your provider. Some work with the standard phone apps, some have their own apps, but most don't seem to offer it at all here in Germany. One even sends you an audio MMS instead and just calls that "Visual Mailbox". It's crazy to me that such a basic and useful feature still isn't just a standard thing on all phones.
My husband and I have the same provider but different brands of phone. I have visual voicemail, he doesn't and my phone is the older one. It seems like Samsung and Apple are the only ones to even offer the app so far.
I have a Samsung S20 and it has visual voicemail, haven't dialed my voicemail in years. I assumed most phones from the past couple years had it, but my husband's Google pixel doesn't,.