You will need to start by looking at higher-quality chocolates.  I totally understand that these also may cost more, but these chocolates are more likely to have a shorter list of ingredients and be easier to distinguish as vegan.  You can definitely look for chocolate brands that are labeled as vegan, but keep in mind that some chocolate bars may be vegan even though they don’t carry that word on their label.   Check the ingredient list and make sure it doesn’t contain any dairy such as milk, milk solids, milk fat, or a crazy long list of ingredients. For a list of brands to consider or more info about how to choose a vegan chocolate bar, check out this article by The Spruce Eats.