From page range to article number

Traditionally, scientific articles have been identified by volume, issue number and page range (e.g. Vol. 12, (3), pp. 123-129). As more journal articles are being published continuously online rather than in printed issues, many publishers have started to use article numbers instead of page numbers, for a faster publication process.

Example:

Instead of:

Tam, W., Ma, C. (2014) Bipolar/rod-shaped microglia are proliferating microglia with distinct M1/M2 phenotypes. Scientific Reports, 4(2), 123-132. https://doi.org/10.1038/srep07279

[NOTE: Partially made-up numbers in the reference above.]

Publishers use:

Tam, W., Ma, C. (2014) Bipolar/rod-shaped microglia are proliferating microglia with distinct M1/M2 phenotypes. Scientific Reports, 4, Article 7279. https://doi.org/10.1038/srep07279

Keep in mind:

EndNote has a field for Article Number within the references, however, the field may be incorrectly filled in or hidden. Therefore, when you import your references, check that the article number (if there is one) is in the right place.
Sometimes the article number ends up in the page number field or vice versa.
For some reference styles, it may be necessary to include the article number in the field for Pages as well, in addition to the Article Number field.

Therefore, if necessary, you should edit the reference manually.