While the term Ockham's razor does indeed find its origins with William of Ockham's sentiment "plurality should not be posited without necessity." However, William of Ockham did not come up with the term Ockham's razor, this was done 500 years later, and the specific phrasing of the principle as "entities are not to be multiplied unnecessarily" is credited to John Ponce. This demonstrates that Ockham's razor is not owned by one individual; many people have added their insights to shaping the principle over the centuries. As a result, one cannot take some purist interpretation which only looks at the ideas of William of Ockham when considering the scope of Ockham's razor, for not only has the razor evolved, but Ockham is not even the creator of the razor, merely the inspiration.
My understanding of the principle "entities are not to be multiplied unnecessarily," is that if one is presented two theories, both of which can equally explain and predict a specific phenomenon (i.e. all things being equal), then the one which introduces the fewest new assumptions (multiple entities) is preferred. This makes sense, for if all things are equal, that is, if the two competing theories can both predict and explain equally well, then assuming the existence of multiple entities becomes unnecessary, for the competing theory is just as successful yet without relying on an appeal to an unknown entity. You will find that this is not the simplest explanation. To say that it is the simplest explanation could mean a lot of things. Having one single answer for everything would be very simple; for instance "X is caused by magic" is a very simple answer in some sense, particularly when compared to explaining a phenomenon such as magnetism, however this is not favored by Ockham's for it requires the introduction of an unknown entity, namely magical powers. Thus Ockham's razor IS NOT the simplest explanation, unless your understanding of simplest in this context is the theory which introduces the FEWEST NEW ASSUMPTIONS. This is an important distinction because while the one which introduces the fewest new assumptions (multiple entities) can be seen as the simplest, the simplest can be seen as being many things other than the one with the fewest new assumptions. As a result, it is not entirely accurate to say Ockham's razor is the simplest.
With the distinction between the simplest theory and the one which introduces the fewest new assumptions made clear, this article will now consider the charge that Ockham's razor argues that "simplicity" is a sufficient condition for a theory to be true. Ockham's razor is not an absolute, nor does it maintain that a theory is necessarily true by virtue of its simplicity. Ockham's razor maintains that the "simpler" (again, simpler meaning the one which introduces the fewest NEW assumptions) is PREFERED. It is not a rule of logic, rather it is a heuristic, meaning that it is by definition does not necessitate truth, but only acts as a tool to help find a preferential theory, between two competing ones.
In conclusion, Ockham's razor is not accurately interpreted as merely the simplest explanation is the correct one. This is false on two grounds. First, it is not just the simplest, but more specifically, the one which introduces the fewest new assumptions. The second is that Ockham's razor does not necessitate truth. It makes no claims that "simplicity" is sufficient for truth. It is not a rule of logic, and makes no claims to. It is however, a helpful tool in preferring one otherwise equal theory over another.
Here is a short video on Ockham's razor; I encourage you to check it out: