What are the differences between pinned bases and fixed bases?

When structures like portal frames are connected to the base foundation, engineers have to decide the degree of fixity for the connection. In general, the two common design options are pinned bases and fixed bases. Pinned bases have the advantage that the design of foundation is made simple so that some cost savings may result. However, fixed bases design provides additional rigidity and stiffening to the structures and the stability of the structures can be enhanced. Therefore, the use of fixed bases helps to improve the structural performance of the structures

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.