There are two endpoints of API that you can use.
First is to get the contact database structure, so load the contact base from CRM and consult it for second endpoint
Second is to add a new contact to the database.
So what you can do is to add contacts to OML database, charging it in OML
THe other thing you can do is the CRM to OMniLeads interaction, read it carefully. https://documentacion-omnileads.readthedocs.io/en/stable/crm_integration_crm2oml.html.
Best regards
