In your opinion, what is the most important and essential accounting certificate for junior accountant ?

FOR ALL ACCOUNTANTS JUNIOR & SENIOR ICDL OFFICE + ENGLISH LANGUAGE + Professional Accounting Certificate CPA CMA CFM CIA IFRS + EXPERINCE + Desire For Development By Assessing Performance and the Desire to Succeed

Generally there is no exact answer, it depends on you and what you would like to be in the future.
If you like external audit and would like to work with famous auditing companies (big 4) then CPA and ACCA are recommended.
While for managerial accounting CMA (easy) or CIMA (really harder but very beneficial) will be great.
If you are going for investments and property management then CFA This is small brief fir junior accountant but later MBA or Master Degree will add value for your career bath development At the end, all continuouse development for you knowledge and professionality will be very helpful to get a better jobs

Basically when you are giving someone the Post of Junior Accountant this will not only be dependent upon the qualification but there are multiple directions which you need to check out which may be as fallows;
1- Qualification (May be Bachelor degree With Major in Accounting.)
2- Experience (You can't say every time because sometime people with a very good experience in accounting are on good positions although they may not have any higher qualifications)
3- Type of Company (Some very good companies hire candidates as Junior accountant although they may have very good qualification and experience, still they are given the Junior Posts because they want proper training of their employees.) So the summary is that being an accountant you may face a very diverse type of issues one may not be able to decide only on the basis of Qualification only, but indeed there are multiple issues to be considered.

Graduation in Accounting Subjects with computer knowledge & Certification in Accounting Softwares

Graduation degree and a year experience enough for any junior accountant.