Anyone knows how can I see in the editor what is the index of a vertex on a mesh?

Every vertex has an index number. How can I figure out what is this number? Must be some flag or some command or something

Also if possible anyone knows if this vertex index changes on build or randomly? Or once the mesh is imported in unreal that index number will always be the same. I want to build some logic around where this vertex is. if this number changes obviously the vertex I want to use will not be the same.