You can get metadata information for input files with the _metadata column.For file path you would use _metadata.file_path.

df = spark.read \
  .format("csv") \
  .schema(schema) \
  .load("dbfs:/tmp/*") \
  .select("*", "_metadata.file_path")

More details - https://docs.databricks.com/aws/en/ingestion/file-metadata-column