You can report obvious and persistent vandals at Wikipedia:Administrator intervention against vandalism. Before posting there, a final warning in an escalating series should have been posted to the user's talk page (for example {{Uw-vandal4}}, {{Uw-spam4}} or {{Uw-speedy4}}), and the user must have vandalized within the last few hours, including after the final warning was given. Various warning templates can be found at Wikipedia:Template messages/User talk namespace. Your block request is unlikely to be acted upon unless you follow these steps. Cases that are not simple vandalism can be reported at WP:AN/I. Of course, in conjunction with warning against and reporting vandalism, you have the ability, mandate and are encouraged to revert all instances of vandalism you find yourself.
This template should always be substituted by prefixing "subst:" inside the template code. Thus use {{subst:Reportvandal}} rather than {{Reportvandal}}.
You can indent the template, by typing :{{subst:Reportvandal}}.
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