Migrating data from old to new while trading in old for new.
I intend to upgrade from my MacBook Pro 15" (mid 2014) to the iMac 27" 2020. However, I will be trading in the old for the new. What is the best course of action to migrate all data from old to new? Is this something that can be done at the apple store upon trade in/purchase? Or do I need to move all the data to an external drive prior to the purchase? I do not have a "Time Machine" setup currently.
MacBook Pro Retina