Spark-2.2.0 onwards simply use pip install pyspark and get pyspark installed in your machine.
pip install pyspark
For older versions refer to the following steps.
Add Pyspark lib in Python path in the bashrc
Also, don't forget to set up the SPARK_HOME. PySpark depends on the py4j Python package. So install that as follows
pip install py4j
If you want to know more about Spark, then do check out this awesome video tutorial: