I am new to this field. I have published one review paper in a journal recently. Do journals issue certificates after publishing manuscripts?
Generally, once you have a manuscript published, you don't receive a certificate, but you get something far better and far more practical - a published paper that would be read by a wider audience and potentially, cited (which can be considered as validation of your work). Additionally and importantly, you'll have a bibliographic record that you can add to a website, CV, Christmas Card etc. - that is a true 'certificate' or your work.
Having said all that, a little while ago, I received a small A4 'certificate' for having an article published as a featured article - but that is very journal specific.