First, navigate Programs > Registration. Click on the three dots at the right end of a default question, then select “disable”.
By disabling a question, the question will no longer appear to users when they register on the platform, and won't be factored in to the pairing process.
Be especially aware that skills and goals questions are important to allow features like Mentorship Agreements and Final Assessments on progress. Disabling these makes the platform less powerful in reporting.