How to protect your data from being stolen

Sadly, you can't. But you can protect yourself from identity theft, as Bruce Schneier explains:

The reality is that your sensitive data has likely already been stolen, multiple times. Cybercriminals have your credit card information. They have your social security number and your mother's maiden name. They have your address and phone number. They obtained the data by hacking any one of the hundreds of companies you entrust with the data­ -- and you have no visibility into those companies' security practices, and no recourse when they lose your data.

Given this, your best option is to turn your efforts toward trying to make sure that your data isn't used against you. Enable two-factor authentication for all important accounts whenever possible. Don't reuse passwords for anything important -- ­and get a password manager to remember them all.

Do your best to disable the "secret questions" and other backup authentication mechanisms companies use when you forget your password­ -- those are invariably insecure. Watch your credit reports and your bank accounts for suspicious activity. Set up credit freezes with the major credit bureaus. Be wary of email and phone calls you get from people purporting to be from companies you do business with.

At the very least, download a password safe (like the one Schneier himself helped write) and make sure that you use a different, random password for everything.

Apropos the last sentence in the quote from Schneier, scammers here in the U.K. have turned to spoofing caller ID to make people believe that phone calls come from their bank. https://www.theguardian.com/money/2019/may/11/number-spoofing-290000-returned-to-readers-scammed-out-of-their-savings So, don't trust your phone when it says your bank is calling you. It may be a scammer faking the caller ID. Apparently, it's not hard to do.