Social Security Number

I am an insurance agent and Ive created a website that potential customers use to and enter their personal information for an auto or home quote. Several of my companies require a social security number in order to get an accurate quote. Is it safe and legal to ask for the customers social? 

It would be better to link to an external compliant service that secure personal information. 

For example, Squarespace Form Blocks aren't secure enough to be used for health information as defined by HIPAA (Health Insurance Portability and Accountability Act).