If a Race that you have registered for has enabled Digital Bibs, you will be able to access them from your Profile under the Upcoming Events Tab through the View Digital Bib link:
You will also be able to access them via the Digital Bib tab on your Registration Management page by logging onto RunSignup, navigating to Profile > Upcoming Events > Manage Registration > Manage Registration. Depending on the Race page's theme, the Digital Bib option can be either located on the top of the page or on the left of the page. See screenshots below for reference.
From this page you will be able to share or print your Digital bib using the icons above the bib: