Parquet is columnar store format published by Apache. It's commonly used in Hadoop ecosystem. There are many programming language APIs that have been implemented to support writing and reading parquet files.
You can easily use Spark to read or write Parquet files.
Code snippet
import org.apache.spark.sql.SparkSession
val appName = "Scala Parquet Example"
val master = "local"
/*Create Spark session with Hive supported.*/
val spark = SparkSession.builder.appName(appName).master(master).getOrCreate()
val df = spark.read.format("csv").option("header", "true").load("Sales.csv")
/*Write parquet file*/
df.write.parquet("Sales.parquet")
val df2 = spark.read.parquet("Sales.parquet")
df2.show()