A normative statement in economics is like a normative statement in any other academic subject--it is a statement about something with an implicit value judgment or moral claim.
It is distinct from a descriptive statement that is supposed to be value/ideologically neutral.
For example, a descriptive statement in economics could be something like, 'Social Security is set to go bankrupt by 2050.' Whereas a normative statement would be something like, 'Social Security is set to go bankrupt by 2050 and thus must be saved to prevent a huge boom in elderly poverty.'