As per section 7.b of the Open Model Initiative (OMI) Charter all code submitted to the OMI needs to be accompanied by a Developer Certificate of Origin (DCO) sign-off that is submitted through a TSC-approved contribution process.
The sign off needs to be using your legal name, not a pseudonym. Git has a built-in mechanism to allow this with the -s or --signoff argument to git commit command, providing your user.name and user.email have been setup correctly.
If you have any questions, you can reach us on the OMI discord; first, join the Discord server then join the dev-chat channel.