Authorship
"Authorship entails a public acknowledgment of scientific or professional contribution to a disseminated piece of information." ~APA.org
This determines who is listed as an author on the publication. If you are collaborating with others on your publication, you should discuss authorship early in the process. Re-discuss if people are added to or removed from the team.
Publishers may address authorship for their publications. Here are two examples:
If you have questions about authorship, contact the publisher. You may want to acknowledge contributors in a footnote or other appropriate location if they are not authors.
Author Order
Typically, authors are listed in the order of contribution amount, with the first listed author contributing the most. The first author is usually considered the most prestigious spot because it suggests the most significant contribution and is the most visible in citations. However, some disciplines consider the last author position the most prestigious.
Be sure to address author order with your collaborators. You may need to discuss it again as the project evolves since contribution levels may change over time.
Primary/Corresponding Author
Publishers typically correspond with only one author for more efficient communication.
That author is usually labeled the primary author or corresponding author. Read the
publisher's description of this label to ensure you select the correct author.