I assume you mean for elk, deer, or pronghorn? If so, start on this page:
All deer, elk and pronghorn hunters must complete and submit an online hunter report, for each tag issued, within 10 days of harvest or within 10 days of the close of the season for which their tag was valid.
The online version links to our vendor, or you can call into the Wildlife Bureau at the number listed.
Congratulations on your harvest!