If you outsourced your tax return to a tax preparation chain like H&R Block, you may be asked by phone or in person if you'd like to add their protection plan to your service.
This is why, depending on the provider and what the audit protection plan offers, audit protection plans gently toe the line between “marginally useful financial service” and “an outright scam.”
Most people with tax situations simple enough to confidently self-prepare their tax returns tend not to be in groups that are common audit targets. Many users buy these plans for peace of mind, nothing more.
But even if you gain temporary access to a qualified tax professional through a protection plan, it isn't a guarantee you'll have a successful outcome or that they can handle your case promptly.
Even if the audit protection plan gives you access to a qualified tax professional, they are only paid to help you with a specific problem rather than research or defend highly-specific and complex tax issues.