VertexOutDegree

VertexOutDegree[g] gives the list of vertex out-degrees for all vertices in the graph g.

VertexOutDegree[g,v] gives the vertex out-degree for the vertex v.

VertexOutDegree[{v->w,…},…] uses rules v->w to specify the graph g. 

Please visit the official Wolfram Language Reference for more details and examples on core symbols.