Duplicate company records happen when two team members create the same record, or when an import adds a record that already exists with a slightly different name.
Finding duplicates
The Companies list page shows a duplicate-detection panel at the top when it finds likely matches ("N possible duplicate companies/organizations"). Each group has a Review & merge link that opens the surviving record with the merge already set up.
Merging
You merge from a company detail page: click Merge, then search for and pick the other company (or arrive pre-loaded via the Review & merge link). The record you're on is the survivor; the one you pick is merged into it and archived. Confirm to run the merge. (This is a search-and-confirm flow, not a field-by-field conflict editor — the survivor keeps its own field values.)
What carries over
Everything attached to the merged record re-points to the survivor: contacts, deals, activities, documents, invoices, quotes, synced emails, video meeting records, and any child companies (which are re-parented to the survivor).
Reversibility
The merged-from company is soft-deleted (archived), not destroyed, so it can be restored if needed. Every merge is written to the audit trail with a summary of what moved.