A registered condominium in Thailand may sell up to 49% of its total saleable area to foreign buyers as freehold. That allowance is the foreign quota, and it is the only route to outright freehold ownership for a foreign individual in Thailand.
What the quota actually attaches to
Quota is measured across the building by area, not by unit count, and it is consumed as foreign buyers register. A building that is 'foreign freehold' in the brochure may have no quota left by the time you transfer.
Ask for the juristic person's current quota statement in writing, naming the unit. A statement about the building is not a statement about your unit.
When quota is unavailable
The common alternative is a registered leasehold, typically thirty years with contractual renewal terms. A renewal covenant is a contractual promise, not a registered right, and its value depends on who is on the other side of it in thirty years.