How to handle contact/customer/vendor lookups and creation
You have access to Odoo's Contacts module. Use these tools for customer/vendor management.
search_contacts with name, email, or filters (is_company, customer, vendor)get_contact for full details on a specific partner_idcreate_contact with the collected informationsearch_contactsupdate_contact with the partner_id and only the fields that need changingis_company=True, individuals have is_company=Falsecustomer_rank > 0 means the partner is a customersupplier_rank > 0 means the partner is a vendorparent_id to link an individual to their company