Do I have to use the cable that came with the iPhone 12? I don’t have an adapter to plug it into the computer

Hey there Micajones07!

Apple strongly suggests that their customers use the cables meant for their devices.

You may use a different cable as long as it is lightning. I’d strongly suggest checking out this article before making any decisions.

Identify counterfeit or uncertified Lightning connector accessories - Apple Support

Good luck,

Jitter

Hey there!

If your looking for a matching block for that cable you can pick up one for $20 USD here

And as said above by bumbleben0, you can use any previous chargers that you may posses from older iPhones.

Good luck,

Jitter

If you already have a lightning cable that you used to charge your previous iPhone, that will work with your new iPhone 12.