Sure, here's an outline of how such an article might look. I have inserted h2 tags to represent the subtitles for each section. -----------------

Introduction

Living and working in Canada has numerous privileges. One of the key essentials is having a Social Insurance Number (SIN). This article provides a comprehensive guide on applying for a SIN through a website, mobile app, or a call centre.

Understanding Social Insurance Number (SIN)

In this section, I would talk about the importance and use of a SIN number in Canada.

The Need for a SIN in Canada

This part would explain why people need a SIN number in Canada – the benefits it offers and its legal implications.

What You Need Before You Apply

Here, I'd list the requirements for applying for a SIN number in Canada, both for citizens and non-citizens.

Applying for a SIN Through the Government of Canada Website

This section will guide readers on how to go about the online application, what information is needed, and detailed steps on how to fill the form.

Applying for a SIN Through the Mobile App

It would entail steps on how the readers can apply for a SIN via the mobile app, its benefits, and a quick rundown of the process.

Applying for a SIN Through a Call Centre

A description on how to call into the SIN helpline to apply for a SIN over the phone, along with potential questions that might be asked during the call.

Processing Time and Delivery Method

This section would describe the typical processing times for a SIN application, how they will receive their SIN, and what to do if they haven't gotten it after a certain amount of time.

What to do if Your Application is Denied

Here the readers are guided on what steps to follow if their application gets rejected.

Conclusion

A summary of the entire article and a call-to-action encouraging readers to start their SIN application process.

------------------- Please note that the actual content may vary according to your specific needs, up-to-date laws and regulations, and the details you would like to include to make this a high-quality, informative, and engaging piece.