What is a Privacy Policy?

While most Privacy Policies will share certain features and structure, there is no one-size-fits-all Privacy Policy. As every website is unique, so is every Privacy Policy.

A Privacy Policy is a legal document specially crafted to disclose what personal data your app or website collects, what is done with that information, and how that information is kept secure. Since the methods your website uses will be different from another website, your Privacy Policy will also be different.
It's important that your Privacy Policy covers all relevant aspects of your services so your users know what happens to their personal data and so that you are compliant with all relevant laws and regulations.
As you can imagine, Privacy Policies come in many shapes and sizes depending on the legal needs and services provided by the app or website.
For example, the Privacy Policy for a start-up website may be very short and simple, but the Privacy Policy for Amazon.com is multiple pages long with many sections and clauses in order to cover all of the services they provide and data they collect to deliver such a variety of features.
For this reason, there is no Sample Privacy Policy Template or one-size-fits-all solution. You need to ensure your Privacy Policy is complete from a legal standpoint, as well as informative and helpful to your users.
Different clauses in your Privacy Policy for the services you use
Different clauses for different services

Privacy Policies are composed of a few common elements that should be present in every situation. Beyond that, different clauses will be included depending on the types of services your app or website offers.
For example, a website that processes credit card information will have a section in its Privacy Policy discussing how that credit card information is encrypted and stored so as to keep it from unauthorized access.
In this section, you will find a variety of clauses that are commonly included in Privacy Policies depending on the services offered. Clauses such as these will be mixed and matched to create your Privacy Policy, with each clause being individually tweaked to suit your specific needs. What information do you collect?
This is a necessary part of any Privacy Policy, disclosing to your users what types of information your app or website collects. This crucial clause lets your users know right from the start whether you will be collecting data they are comfortable sharing.
For example, a website could simply collect an email address for their mailing list during registration. This would be very different from an app the collects the user's name, location, email address, and payment information.
Users have the right to know what kinds of information you collect from them! Below is an example of this clause from Apple:
Apple Privacy Policy: What Personal Information we Collect clause

Note that most privacy laws also dictate that you may only collect personal information that is reasonable and proportional to provide the services that you offer. Even if you disclose what information you are collecting, you need a reason to be collecting it.
What do you do with that information?
In addition to disclosing what types of information you collect, you must also disclose how that collected information is used. This necessary clause informs users about what is done with their personal information after it has been collected.
For example, a website may collect a user's name and address in order to deliver products that were purchased online. It is understandable that this information is necessary and no additional information is collected beyond what is needed. This would be very different from a website that collects a user's name and address and then sells that information to a third-party for the purposes of sending marketing material.
While both websites collect the same information, it is important to know how that information is used after it has been collected. Most privacy laws also dictate you only use the personal information you have collected for tasks necessary to performing your services.
Below is an example of this clause from Apple:

Apple Privacy Policy: How we use your personal information clause How is that information kept safe?
When collecting personal data from any individual, there is an obligation to keep that information secure and accessible only to authorized persons. If you are to be trusted with handling personal information about users, you must take appropriate measures to keep that information safe.
For example, if you store customer's credit card information to expedite future purchases from them, that sensitive information needs to be securely stored behind firewalls and SSL encryption to keep unauthorized persons from hacking and stealing that data.
Over the past few years, data breaches have affected millions of internet users and many of the companies involved faced serious legal and financial burdens as a result. If you are going to be handling or storing personal information, it is your responsibility to make sure that information does not fall into the wrong hands and disclose your methods of safeguarding it to your users.
Below is an example of this clause from Apple:

Apple Privacy Policy: Protection of Personal Information Clause Do you have users under the age of 13?
This special clause pertains only to certain apps and websites, and is regulated primarily by COPPA (the Children's Online Privacy Protection Act). While protecting the privacy of everyone is important, it is especially important in the case of minors. COPPA sets forth special requirements for apps and websites that collect data from kids, resulting in an additional clause within the Privacy Policy of apps of websites that are intended for children.
If your app or website has young users, you must read and comply with the regulations set forth by COPPA!