As a very rough first filter, for papers in the area of natural sciences, check if the paper is indexed in Pubmed (https://pubmed.ncbi.nlm.nih.gov/). Every legimitate peer-reviewed journal in that area is indexed there, anything that is not indexed is almost certainly a dubious journal. But you can't use this the other way around, Pubmed still contains some journals that publish questionable stuff.
Beyond that you can look a bit at the impact factor of the journal, you can generally find it by just googling for the name of the journal + "impact factor" or on the Wikipedia page of the journal. But it is kinda hard to interpret this on its own, and it does not translate directly into credibility. A high impact factor shows that articles in that journal are cited very often, and you can assume that journals with high impact factors generally have a reasonable peer review system. But that doesn't say much for a single paper, reputable journals can easily fail in individual cases.
The Pubmed check generally filters out most of the journals that would just publish anything without real review, so it's the most useful filter in my opinion. I would not try to gauge more meaning than that from the journal and focus on the individual article.
Beyond that you can look a bit at the impact factor of the journal, you can generally find it by just googling for the name of the journal + "impact factor" or on the Wikipedia page of the journal. But it is kinda hard to interpret this on its own, and it does not translate directly into credibility. A high impact factor shows that articles in that journal are cited very often, and you can assume that journals with high impact factors generally have a reasonable peer review system. But that doesn't say much for a single paper, reputable journals can easily fail in individual cases.
The Pubmed check generally filters out most of the journals that would just publish anything without real review, so it's the most useful filter in my opinion. I would not try to gauge more meaning than that from the journal and focus on the individual article.