How do I update my apple ID on my Mac?
I have os x 10.10.5 and need at least 10.11 for Turbo Tax. When I try to download version 10.11, I can't find anything earlier than 10.11.6 and 10.11 is required BEFORE downloading 10.11.6. When I tried to upgrade to High Sierra, a previous apple ID is showing and I can't change it. I don't know that password and it isn't my current apple ID. I am completely stuck. I need both a newer os AND to change the apple ID on my Mac.
iMac