How do I transfer personal music from my iPhone 12 to iPhone 16?

Thanks to all of you for your replies. My concern is that the last time I upgraded my iPhone as well as the last time my wife upgraded her iPhone, the transfer process was seamless (at least as I remember it) and those two phones contain all my CD's I uploaded into Music/iTunes years ago. This is the first time they did not transfer. The telephone tech support people could only offer to sell me a subscription to Apple Music as a solution. I specifically do not want the temptation/bother of having a million song music collection/app. I want to have the music I purchased in my library and keep it there. I have been buying a lot of music from iTunes Store, so I think I've paid my dues, so to speak. I don't think I should have to round up old computers (the one I originally loaded my CD's onto has been recycled by Apple). Somehow Apple (we went through the Apple Store in San Luis Obispo CA) managed to sell us a new phone multiple times and get our music transferred. I will go back to the store and see if they can repeat their seamless magic. After all, the sales clerk promised me that ALL of my data would transfer AND the ONLY reason I was buying a new iPhone was so I would have more memory to story my music as well as my other data on my phone. Ironically, when they deleted my music from Music, I no longer have enough data to fill up my old phone's memory. Again, thank you for your replies. I hope to update you after my visit to the store.

I’m now thinking I was mentally misled by the store employee who seemed distracted and not wanting to take much time with me. He said several times that all of my data would transfer if I followed the prompts. Neither he nor the prompts ever suggested I needed to synch with my computer iTunes to complete the process. I was just left with missing music. I realized this only after all my emails and Apple Car Play vanished as well. These too required tech calls, the tech and unable to solve the Car Play issue which I eventually solved myself by buying a new USB cable to connect to the USB port instead of the USB-C in my EV-6. Thank you for all your kind assistance. I synched with my computer and now have much more music than I wanted on my phone because albums I deleted previously returned. I wish the store rep had been correct and all these extra steps were not necessary so that a new phone simply continued where the old one left off.

My personal music comes primarily from CD's. These also did not transfer when I bought a new Apple computer. (and the new computer does not have a CD player)