Setting up call forwarding from iPhone 14 Plus to iPhone 16 Pro Max

I have an iPhone 14+ and an iPhone 16 Pro Max, which is Spectrum and the 14+ is t mobile and Verizon I believe. I have 2 lines on the 14+. I want to use call forwarding to my iPhone 16 Pro Max. For my one line at times! I see a place in my settings for Spectrum that says to cancel call forwarding star 73. Does that mean it would stop my number from being forwarded or any numbers coming in to my 16/Spectrum and how would I make my 14 call forward to my 16 when I need it to? Is it still star 72 like it was way back when thank you

[Re-Titled by Moderator]

Original Title: Using call forwarding