What API does JIRA team recommend to be used for fetching editable issue fields?

[Samrat Dutta]

Hello Jira Community,

We see two APIs, ie Create Issue metadata and Edit issue metadata that returns fields to be sent during create or update. 
Is it okay if I used Create Issue metadata in both cases of create and update?
And if not, why?
Can someone pls advise? 

[Sunny Ape]

> Is it okay if I used Create Issue metadata in both cases of create and update?

Nope.

1. Create issue metadata is for when issues are created.
2. Edit issue metadata is for when issues are edited (which is just another name for updated).

You already seem to have this knowledge, as per your other question How to remove a Parent Epic from an Issue.