Vegans get all the necessary nutrients (except for vitamin B12) if they eat a balanced diet. If you are worried about developing any deficiency you may want to check out blogs by vegan doctors like
https://nutritionfacts.org/. It provides a host of useful information unveiling the common myths about the vegan diet. Also, if you're a beginner to veganism there's an informative guide for vegan beginners at
https://happyvegan.life/. I hope they will help to address your concerns.
