Here is some translated information about the census, provided by the Hungary State Archives:
Transcarpathian Territorial State Archives 1921 census documents
One of the newly emerging countries after the First World War was the Czechoslovak Republic, proclaimed on October 28, 1918 in Prague. The territory of present-day Transcarpathia, also known as Podkarpatska Rus, came under the rule of this country.
The 1921 census in Czechoslovakia was adopted by the National Assembly of the country on April 8, 1920, Resolution 256/1920. s. ordered by law. The law provided that the census was to be conducted everywhere between November 1, 1920, and March 31, 1921, including in Transcarpathia, which is now part of Ukraine. The material of the census has survived almost entirely.
During the digitization of the approximately 270,000 pages of documents kept in the Beregszász branch of the Transcarpathian Regional State Archives, the summary sheets (settlement, street name and number, with the name of the owner) and census forms indicating the data of the inhabitants of the given dwelling (name, date of birth, place, mother tongue, religion, occupation, etc.) based on the houses (flats) of the settlements. The latter can be an extremely rich source of both historiography and genealogy.
The pre-printed bilingual questionnaires - Czech and Hungarian - were filled in a smaller part with a pen and a larger part with a pencil.
The conservation and digitization of the documents was carried out by the Archives of the Capital of Budapest in 2017 with the support of the Hungarian Ministry of Foreign Affairs and Trade.