"A co-author is any person who has made a significant contribution to a journal article. They also share responsibility and accountability for the results.
If more than one author writes an article, you’ll choose one person to be the corresponding author. This person will handle all correspondence about the article and sign the publishing agreement on behalf of all the authors. The corresponding author is responsible for ensuring that all the authors’ contact details are correct. You should all agree on the order in which your names will appear in the article."
"If you are a named co-author, this means that you:
"Your affiliation in the manuscript should be the institution where you conducted the research. You should also include details of any funding received from that institution. If you have changed affiliation since completing the research, your new affiliation can be acknowledged in a note."
Authorship - a 40 minute webinar from Elsevier covering the ethics of authorship:
"An ‘author’ is generally considered to be someone who has made a substantial intellectual contribution to a published study. While in some fields this can lead to an author list spanning several pages, that’s not the case for the average paper. In this module, we guide early career researchers through some of the general rules about who should be included and how they should be listed. We also highlight some pitfalls you should always avoid, whatever your field, such as ghost and gift authorship, and we offer tips on how to handle authorship disputes. "