Create offline maps from desktop computer

I'm reopening a thread from five years ago. During last year I tried several times to create an off line map on my computer and then try to synch or pull it up on my iPhone app to no avail. Five years ago, there was a post saying this feature was being worked on...what is the status? I'm with others who want to use the larger display of a computer screen to create my off line maps and not have to do that kind of work on my phone. Appreciate any updates the community may have, thank you.