Connecting iPhone 15 Pro Max and MacBook

Connect them to do what exactly? What are you trying to accomplish?

You can physically connect them with a USB-* cable to sync content using the Finder (iTunes if the Mac is running macOS Mojave or earlier).

click here ➜ Sync your iPhone, iPad, or iPod using your computer - Apple Support

Beyond that, things like Handoff, and other Continuity features require both devices to be logged in to the same Apple Account.

click here ➜ Continuity features and requirements for Apple devices - Apple Support

Things like Airdrop can work directly.

click here ➜ Use AirDrop on your iPhone or iPad - Apple Support

If you explain what you are trying to do, we can be more specific.

How do you wish to connect the two?

• Do you want to use the Mac for phone calls by using the iPhone?
• Do you want to transfer files?
• Do you want to sync Music?
• Are you referring to needing an adapter for a physical wired connection?
• Are you trying to AirDrop from one device to the other?