What security practices should tax preparer's put in place?

What are best practices when it comes to security, tax payer's information, and communication.,What should a savvy taxpayer be aware of?

There are times some tax expertise matters. I would think if the tax preparer had a website portal with a way for the tax payer to login with an anonymous user id, a password, and multi-factor authentication that would be the best way to go.

However, I've heard some tax preparers send draft tax documents through Citrix (or other) where the taxpayer needs to click a link and only put in their name and email address and the documentation is fully available? If this is "secure" - how?

When searching for a tax preparer, what security practices would you want to see put in place?