How can I get my sharepoint 365 master page and page layout to appear across my intranet site?

Question

I'm setting up a SharePoint 365 intranet site for my company and we want to use our own designs. However, my own Master Page and Page Layout are not being seen either in new or existing pages.

In Design Manager I've uploaded my own HTML for a Master Page and created a new Page Layout. Both look fine in preview and report no errors. I've published both the Master Page and Page Layout. In Publish and Apply Design, I've selected my newly published master page as both Site Master Page and System Master Page. However, although my new master page is appearing on system pages, there is no sign of it on the intranet site pages.

Perhaps I am missing a step somewhere? I've been studying the Microsoft docs under Building sites for SharePoint, including Apply a master page to a site in SharePoint but cannot see anything amiss.

Answer 1

As far as I know the master page and page layout will work with the publishing feature and Application pages. So when you visit the pages under the Site Pages they do not get the master page and page layout.

Pages under the Site Pages library are wiki pages and hence do not get the Master page and page layout applied.

Answer 2

It seems it is not currently possible to apply a custom master page to 'modern' pages. The most recent documentation I've found is: https://docs.microsoft.com/en-us/sharepoint/dev/solution-guidance/modern-experience-customizations-customize-pages

These customizations are currently not supported for "modern" pages:
... Custom master pages (more extensive branding will be supported later using alternative options)...