1. There is no need to add or delete authors to the journal before submitting. Authors can be added and deleted with the consent and approval of all authors.

2. It is difficult to add and delete authors after the paper is submitted. In particular, some journals are strict with the authors of papers and may not be allowed to add or delete authors. If the magazine has a loose requirement on the signature of the journal author, as long as the reasons for adding the author are explained to the magazine and approved by the magazine, the author can be added and deleted. But just write a statement.