Download the reaper-license.rk attachment from your email onto your computer. Open REAPER and navigate to the top menu. Click > License/Registration (or Activate REAPER ).
: Alternatively, you can simply drag and drop the .rk file directly onto the REAPER application window. License Types and Pricing reaper-license.rk
If you need to backup or move your license, you can locate the file by following these paths: Download the reaper-license