Type approval is manufacturer-level certification that a craft model meets a defined standard, for SOLAS rescue tenders the IMO LSA Code, established by comprehensive first-of-class testing (drop test, swamp test, self-righting) and a Type Approval Certificate, with each subsequent build surveyed to a lighter regime.
The critical point for an owner is that approval is recognised on a per-flag basis: ask for a current certificate listing the flag administrations that accept it, because if your flag is not on the list the certificate has no value to you. See the SOLAS tender compliance guide.