Check at the source
The authoritative list is the HJRS portal at hjrs.hec.gov.pk, published by the Higher Education Commission. Search there by journal title or ISSN — the ISSN is the more reliable of the two, since titles vary in punctuation and abbreviation and several journals have near-identical names.
The result tells you whether the journal is currently recognised and, if so, in which category and in which subject area. Note the recognition cycle the list applies to, because that is the period your answer is valid for.
Take a dated screenshot or save the record. If you later need to show what the category was when you submitted, reconstructing it from a superseded list is difficult.
Search by ISSN, not title. Titles vary in punctuation and abbreviation; the ISSN identifies exactly one journal.
Why a journal's own claim is not enough
Any website can display an "HEC Recognised" badge. Some journals display one that was accurate in an earlier cycle and has since lapsed; some display one that was never accurate.
The same applies to a list forwarded by a colleague or circulated in a department. These are usually snapshots of an older cycle, and they are the most common reason someone discovers a problem only after publication.
The check is quick enough that there is no reason to accept a secondhand answer for a decision this consequential.
Check the international indexing too
HJRS recognition and international indexing are related but not identical, and for most researchers both matter. Verify Scopus coverage on Elsevier's source list and Web of Science coverage on Clarivate's Master Journal List — again at the source, not from the journal's website.
If a journal claims Scopus coverage that the source list does not show, treat that as a serious warning about the journal generally, not merely an error about one claim.
Where your work needs to count both in Pakistan and internationally — for a foreign postdoc, a visa petition, or collaboration abroad — a journal recognised by HEC but indexed nowhere international will satisfy one requirement and not the other. Checking both before submitting is the whole point.