As an on-line encyclopaedia, it is acceptable to use Wikipedia to find general information about topics, particularly those with which you are unfamiliar.
Access Wikipedia by Googling it, or clicking the link below:
However, if you use Wikipedia, it is important that you do not cite, or refer to, it in pieces of academic work, because you will usually be penalised.
Wikipedia is not itself a source. Rather, it is a collection of sources.
So, if a Wikipedia article connects you to a useful source (e.g. a good-quality, peer-reviewed journal article), cite the source (i.e. the article), rather than Wikipedia itself.
For example, the Wikipedia article on Cardiovascular disease (https://en.wikipedia.org/wiki/Cardiovascular_disease) has a section on Risk Factors, with a sub-section for Tobacco. One of the sources cited by this sub-section is an article from The BMJ, a highly-reputable medical journal. Therefore, it is fine to cite this journal article in a piece of work, because it is a reliable source, instead of citing the Wikipedia page that connected you to it.
(Some sources cited by Wikipedia pages may be open access journal contents, or they may be premium content i.e. payment or access via an institutional subscription is required.)
Screenshot of the Wikipedia article on Cardiovascular disease
Screenshot of the Tobacco section of Wikipedia's Cardiovascular disease page, which cites an article in The BMJ
Wikipedia links to the article in The BMJ - it may be downloaded for free, because it is available via open access