You can use the length function for this

from pyspark.sql.functions import length
mock_data = [('TYCO', '1303'),('EMC', '120989'), ('VOLVO', '102329'),('BMW', '130157'),('FORD', '004')]
df = spark.createDataFrame(mock_data, ['col1', 'col2'])
df2 = df.withColumn('length_col2', length(df.col2))

Published notebook to show full example:

https://databricks-prod-cloudfront.cloud.databricks.com/public/4027ec902e239c93eaaa8714f173bcfc/3249...