Add footer without Master page modification in SharePoint (Office 365)

Question

Are there any approaches to add a sticky footer to all pages in SP site without Master Page modifications?

Answer 1

I think you can do it by JavaScript injection. Microsoft recommends using this technique rather than creating / modifying master pages for UI. You can find more information on web:

Customize your SharePoint site UI by using JavaScript

JavaScript injection in SharePoint Online - Office 365 Developer Patterns and Practices

Answer 2

PnP has a great example on adding Header , breadcrumb and footer on all pages without modifying the Masterpage.

It is basically as SharePoint hosted-app that can be deployed on the site collection. After you add and install the app, it will add a user custom action which will inject the javascript on the page. In the below image, you need to click on the Add provision button, which will do the needful.

Core.EmbedJavaScript.HeaderFooter