I'm working on a project using an E-commerce dataset. I'm facing an issue in the data cleaning stage. I have the customers dataset, which has approximately. 1.6 million rows. One of the feature, "Job Title" in the dataset has around 600K Null values. 
Should I Impute the Null values with values like "NA" or "Ignored", Or should i drop them? I can't afford to drop NA rows as they're connected to other datasets. Is there any way to fill these Null values in correct way for this situation? 
This is the first 5 rows of my Customer DataFrame.