question about tails and wifi : DarknetMarketsNoobs | Torhoo darknet markets

i have two older computers, one 2014 macbook that i recently dropped/broke (now need new comp), the other is 2009 macbook. the 2014 one has to be hardwired in to get internet (i use usb stick to boot up tor/tails) which i use an ethernet/usb adapter for. the 2009 does not need an adapter, wifi just exists when i boot up on this one? im curious why this is?
i want a new computer that i can use wifi with but have no idea which computers have this built in? or if they dont have it built in is there an easy fix like a wifi adapter or something i can plug into a usb port?
i'm trying to keep things as simple as possible, i am admittedly not very computer savvy (if you couldnt already tell), i try not to use my phone for doing research about any of this stuff and don't have a lot of time/opportunities/access to get on dread to find answers to this kind of thing. if anyone can explain this and/or help me with a solution i'd greatly appreciate it!

thanks in advance