What is the difference in anti malware like malwarebytes premium and an anti virus? Do I need both or would malwarebytes be enough?
There isn't really a difference between "anti malware" and "anti virus". These are marketing terms used by corporations to sell a product.
malware are used synonymously most of the time.
All of the products that are somewhat sophisticated come in different flavours, which typically involves different licensing types and mechanisms to import signatures. All of these products detect malware in two ways: 1. based on signatures and 2. different kinds of algorithms that look fancy to the untrained eye. This includes: machine learning algorithms, bayesian classification based approaches, heuristic analysis, threat emulation, cloud delivered protection and so forth.
Signatures have been used to detect viruses for ages and - in my estimate - make up for the biggest chunk of detected viruses in the wild.
So when $PRODUCT calls itself something other than an "anti virus" but does all the things, that an anti virus software does, it's probably still an anti virus software. See also here.