If there are 2 or more developers who have developed the App for AppStore, How can they have both of their names displayed below the app together?
Also, do they all need to have a developer account or one is enough?
You need a single paid developer agreement.
Only the legal name of the entity (person or company) that entered into the developer distribution agreement with Apple will be shown on the App Store.
You can have whatever credits you want inside the app
You can also used the description on the App Store page to add a second name. So if you’re developer account is in the name of a company you could put in your description the names of the lead developers.
If it is an individual toss a coin for whose name appears in the developer section then put both names in the description.
It is not possible. That's exactly why there is the enterprise account, so you can have teams and upload apps as a company.
However, it is possible to transfer the app from one account to another, but never two accounts at the same time.
来源：https://stackoverflow.com/questions/51738918/can-i-have-2-or-more-developer-names-displayed-on-ios-appstore