Memory, Teleprompter, Flash Cards during signature talk?

What is the best method of conducting your signature talk to memory when on a stage or presenting your digital product?  I've noticed a lot of information is being presented in the modules and it appears it's by memory, but that's extremely difficult.

Should we memorize our signature talk?  What is the best method to use to guide us when we're on our stages?

During the 10X Growthcon I saw many people using the teleprompter on the bottom of the stage.

(I have a horrible memory and I'm new to public speaking).