I am self employed as a bookkeeper and I started a separate LLC business this year. Do I need to file two separate schedule C's or combine my income from both on one schedule C

If you owned more than one business, you must complete a separate Schedule C for each business.

See https://www.irs.gov/instructions/i1040sc#en_US_2022_publink24329wd0e493

if the llc conducts a business other than you as a bookkeeper a second schedule C is required.