See the following page for detailed renewal instructions by W0IS:
How to Renew Your Amateur Radio License by W0IS
If you complete the renewal form and can't find a link to pay the $35 fee, see the folllowing page for a simple fix:
https://w0is.com/LicenseRenewal/FccCoresPermission.pdf
Thanks to W0IS for decoding the FCC jungle for all of us needing to renew. As many of us know, the US Governement IT systems are among the least user friendly systems in the world.