Dear @Waqas Mahmood, 

look the links. May be useful.

https://www.isj-editors.org/?page_id=486

http://www.issn.org/understanding-the-issn/what-is-an-issn/

Regards, Shafagat

An ISSN is an 8-digit code used to identify newspapers, journals, magazines and periodicals of all kinds and on all media–print and electronic.

An International Standard Serial Number (ISSN) is an eight-digit serial number used to ... The ISSN system refers to these types as print ISSN (p-ISSN) and electronic ISSN ... To calculate the check digit, the following algorithm may be used: ... Also, a CD-ROM version and a web version of a serial require different ISSNs ...

E-ISSN –electonic International Standard Serial Number,

A different ISSN from the print edition (the e-ISSN) is used for the online edition of the journal. This is to enable librarians and other users to distinguish between their print and online holdings. The Online ISSN for ISJ is 1365-2575. The e-ISSN is also used within the structure of the Digital Object Identifier (DOI). Every journal article published by Wiley is allocated a DOI which is then used as the basis on which electronic links between articles can be established. Authors can also use the DOI in article citations.

https://www.researchgate.net/deref/http%3A%2F%2Fbhl.nhm-wien.ac.at%2Fscanlist%2Findex.php%2Fbibs

https://www.researchgate.net/deref/http%3A%2F%2Fimages.webofknowledge.com%2FWOK46%2Fhelp%2FWOS%2FC_abrvjt.html

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=17&cad=rja&uact=8&ved=0ahUKEwjg-YTpgrDSAhVDj5QKHSwoACoQFghmMBA&url=https%3A%2F%2Fwww.researchgate.net%2Fpost%2FHow_are_the

Thanks for valuable input @Shafagat Mahmudova 

Dear

According to Collection Metadata Standards". British Library. Retrieved 14 July 2014.

-International Standard Serial Number (ISSN) is an eight-digit serial number used to uniquely identify a serial publication.

-The ISSN is especially helpful in distinguishing between serials with the same title. ISSN are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature.

-The ISSN system was first drafted as an International Organization for Standardization (ISO) international standard in 1971 and published as ISO 3297 in 1975.[3] ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard.

But e-ISSN (or eISSN) is a standard label for "Electronic ISSN", the ISSN for the electronic media (online) version of a serial.

Please check some sources in the differents links:

I hope to be helpful

Marius

http://www.issn.org/understanding-the-issn/what-is-an-issn/

http://www.bl.uk/bibliographic/issn.html

http://www.issn.org/understanding-the-issn/standardization/

http://www.issn.org/wp-content/uploads/2013/09/ISSNManual_ENG2015_23-01-2015.pdf

ISSN International Standard Serial Number has two types, pISSN, eISSN,

 pISSN:

1. Simply  all those journals which have printed version

2. They have no right to publish online research papers.

3. They may not have own official website.

4. However they can share and disseminate knowledge in form of news and reports etc on the internet through social media and other networks.

4. Print version registered journals some time publish online and charge fees on author. If..then they are fake.

eISSN:

1. Includes all those journals which have  electron version,mean they are published online on the websites only.

2. They journals have no any print version.

3. Publish only electronic version.

4. They have official registered own website

Many journals have both pISSN, eISSN, means such journals publish in print as well as electronic versions.

BASICALLY, ISSN is an internationally recognized registration number which is important like a Vehicle's (Car, bus, motorcycle ) registration number.

More, Dr. Prem Baboo greatly described...

Dear Researchers

Thanks for your valuable comments

Thanks for the great explanations.

E-ISSN is broadcast for scientific journals issued electronically and ISSN for those that are issued traditionally in printed form. I wish you the best in New Year 2019. Best wishes

What is an ISSN?

An ISSN is an 8-digit code used to identify newspapers, journals, magazines and periodicals of all kinds and on all media–print and electronic.

• Which publications are concerned by an ISSN?
• What form does an ISSN take?
• What is its role?
• Where is it displayed?

Which publications are concerned by an ISSN?

An ISSN (International Standard Serial Number) identifies all continuing resources, irrespective of their medium (print or electronic):

• newspapers,
• annual publications (reports, directories, lists, etc.),
• journals,
• magazines,
• collections,
• websites,
• databases,
• blogs,etc.

In many countries, an ISSN is mandatory for all publications subject to the legal deposit.

What form does an ISSN take?

The ISSN takes the form of the acronym ISSN followed by two groups of four digits, separated by a hyphen. The eighth digit is a check digit calculated according to a modulus 11 algorithm on the basis of the 7 preceding digits; this eighth control digit may be an “X” if the result of the computing is equal to “10”, in order to avoid any ambiguity.

e. g.:

• ISSN 0317-8471
• ISSN 1050-124X

What is its role?

The ISSN role is to identify a publication.

It is a digital code without any intrinsic meaning:

• it does not include any information about the origin or contents of the publication,
• it does not guarantee the quality or validity of the contents.

The ISSN is associated with the title of the publication. If the publication is modified significantly, a new ISSN must be assigned.

Where is it displayed?

For a print publication, the ISSN should be shown:

• preferably, in the upper right corner of the cover,
• failing that, on the pages where editorial information is shown (publisher, frequency, colophon, etc.).

For a publication in electronic media, the ISSN should be shown:

• on the homepage or on the main menu, if it is an online publication,
• on any part visible to the naked eye (microfiche header, CD-Rom or DVD label, box, case, etc.), if the publication is on a physical medium.

If a publication is identified by ISSN and ISBN, both of these identifiers should be mentioned.

Useful discussion, we learned

Each version of the publication form of the Periodical must have a separate number: example:

Ādāb Al-Neelain journal

For the printed version is

ISSN: 1585-5523

For the electronic version :

E-ISSN: 1858-8549

The ISSN [International Standard Serial Number] is just a code to identify a periodical publication such as scientific journals and other types of publications. So that there is no indiscriminate use of this resource and in accordance with international and national laws of copyright, in almost all countries there are national agencies that administer this resource and it is through them that they are requested. In India, the office is this: http://nsl.niscair.res.in/ISSNPROCESS/issn.jsp