PhD students are usually not skilled enough to be elected journal editors (as editors are supposed to have years of experience in publishing - lots of publications and also lots of experience in reviewing journal articles) but being a reviewer for a journal or a conference can be a good way to learn more about publishing.
Here is one way to start: You should talk with your supervisor(s) and ask if it is possible for you to assist in the refereeing of a paper already assigned to your supervisor(s) as referees for a journal. Read it carefully, and take part in discussions with your supervisor(s) on the merits of the paper, how to actually measure those merits and which things to look at in a paper in order to assess it. Your supervisor(s) will hopefully have enough experience (and patience!) to tell you how refereeing is done, and done well! There are some ground rules to follow, of course, and you need to learn them well before you can be an active referee for a journal.
PhD students seldom are enlisted as referees by journals, and probably almost never as editors, but it is not uncommon - and it is good practice - for supervisors/professors to allow PhD students to take active part (without any actual responsibility towards a journal) in reading submitted papers.
Most importantly, by doing the above you will learn how your own papers will be handled once they are submitted, and it may change some of your own attitudes towards how you could (or should) write a good paper!
PhD students are usually not skilled enough to be elected journal editors (as editors are supposed to have years of experience in publishing - lots of publications and also lots of experience in reviewing journal articles) but being a reviewer for a journal or a conference can be a good way to learn more about publishing.
From the beginning rather as an author, then as a reviewer, and later as an aditor. Peer-review increases particular skiils need for further scientific development: creative use of own knowledge and development, paper organization, critical thinking. Editorial position allows also for development of managing and organizational skills, need later e.g. in supervising own research team. Especially launching new journal develop project management skills.
Something I do with/to all my PhD students in applied math/mathematical optimization is to tell them to read a good book on the subject of writing and publishing papers - as they are trying their best to write their first ones. In my field a popular book is "Handbook of Writing for the Mathematical Sciences" by Nicholas J Higham, published by SIAM. It is both insightful and witty, and it's a paperback so it doesn't cost much. I also carry with me a list of seven items that any paper on such subjects should contain - without any one of them, it is not complete. :-)
I think that reviewing is invitation basis from the journal editorial board; editors invite people who can help increase the submitted paper quality in agreement with the journal ranking quality and prestige. i don't think that serious journals could invite any phd student or research beginner as referee. May be Phd students could be joined to their supervisor referring work to learn from him/her the referring process and how preparing good papers.
I regularly review papers for Journals, Conferences and occasionally mark a thesis.
I would say yes, it's a good thing, as you will be exposed to what is developing in your field of speciality - a way, of sorts, to keep up with what's happening.
It's probably not the place to learn about new areas, as it is expected that the reviewers are knowledgable on the topic they are reviewing.
Editors must have many years of experience in publishing, lots of publications and papers, lots of experience and skill in reviewing journal articles, and should be english native speaker as well. Thus, I think PhD students are usually not skilled enough to be selected as journal editors, but being a reviewer for a journal or a conference evaluator can be a good way to learn more about publishing, edition and reviewing of papers. TQ.