Custom header across sites and pages

[kenneho]

Hi.

On our upcoming intranet based on Sharepoint Online, we're looking into adding a custom header across all sites and pages. The header may contain additional fields such as information about the logged in user. 

I'm guessing we won't be able to tweak the existing header much, and would potentially need to consider developing our own web part and inject in at the top of every site/page. Is creating a custom web part really the only or best way to add a custom "header" across all our sites and pages? 

[#2 · Accepted solution]

@kenneho You may want to look into developing an SPFx application customizer extension instead of a web part. See Use page placeholders from Application Customizer (Hello World part 2).