When I'm reading papers, I notice that some authors show their ORCID, but most authors don't.
Is showing ORCID a requirement by some journals? Or always optional?
I think all authors should provide readers with their ORCID so that readers can know who they are, where they are now, and how to contact them. But why do most authors not show their ORCID? I hope journals will press all authors to provide their ORCID

I think it is slowly becoming more prevalent. In my field it is common for the article to include thbe corresponding author's ORCID. I know it is not everyone but I can notice a slow improvement over the last few years.



I have a weird anecdote about this. My name was on a paper that had 12 authors and the journal had requested everyone ORCIDs. The corresponding author went to a huge amount of effort to get everyone's (there were foreign exchange and masters students involved) but the journal didn't include them on the article. It was a huge amount of effort that got wasted but I think there must have been a reason that the journal didn't include everyone.

I am probably missing the point, but what's it for? It is just so you can more easily find someone's contact details? I have one I think.