Given a posterior p(Θ|D) over some parameters Θ, one can define the following:
The Highest Posterior Density Region
You can get the central credible interval in two ways: Graphically, when you call summary_plot on variables in your model, there is an bpd flag that is set to True by default. Changing this to False will draw the central intervals. The second place you can get it is when you call the summary method on your model or a node; it will give you posterior quantiles, and the outer ones will be 95% central interval by default (which you can change with the alpha argument).