Myanmar has two World Heritage properties, both cultural: the Pyu Ancient Cities and Bagan
Background
UNESCO's World Heritage states parties page for Myanmar gives the count under the heading Properties inscribed on the World Heritage List 2, and places both in the Cultural category: Pyu Ancient Cities (2014) and Bagan (2019). The Pyu Ancient Cities was the earlier inscription, recorded by UNESCO as the country's first site inscribed to World Heritage List. The same page gives the Acceptance of the Convention: Friday, 29 April 1994, and lists Sites on the Tentative List 15. UNESCO explains that a Tentative List is an inventory of those properties which each State Party intends to consider for nomination, so the fifteen are candidates rather than inscriptions.
In plain words
Tentative List World Heritage Tentative List — A state's own inventory of properties it intends to consider nominating for the World Heritage List.