Is it possible for each subdomain site to have a different header?

Sure, and it’s all done in your theme. Go into Appearance -> Header and set it per site.

Thanks for replying Mike. I have tried to change it via appearance- header but it changes the header for the entire site.
For example.. while I am in the dashboard menu-appearance for the main site, I set a header, then went to the dashboard menu-appearance for the subdomain site, set a different header. Then I view the site and the 1st header I set has changed to the one set for the sub.
I have been researching this since I posted my question and I think I may have to create an index.php in the subdomain folder…?
It’s hard to tell b/c all of the information I am finding is pretty old. So I’m kinda thinking this is stupid easy and I am totally missing something.
I have also noticed that the sample wp page & post are showing up even though I deleted them and also deleted them out of trash, cleared cache.
I am logged in as super admin while doing all of the above.. is there another menu or part of the site I am missing?
The main site is bloggingwithfamily.com I have set the names in the menu to direct to the subdomain, so if you click on Bre in the menu it will take you to bre.bloggingwithfamily.com and that is the page that I can’t get the header to show up on (and you can also still see the &^%#! “hello world” & “sample page” that wont go away)

Still not having any luck.. I would really appreciate help from someone.
I am starting to think something is wrong with my site.
I have been trying to see if using a different theme would help with the above situation but when I activate a theme on a subdomain it changes across the whole site.
I have 3 theme’s installed – the twenty eleven that came with my orig install, the twenty twelve that came with the subdomain and twentyXS that I just installed.
None of the themes are “network activated”. If I enable twenty eleven on main site and twentyxs on subdomain then go to the dashboard in main site-appearance-theme, twenty eleven is active. Then go to subdomain dashboard-appearance-themes, twenty eleven is active – how is this? I do not have twenty eleven “network activated” nor do I have it enabled for the subdomain.
Can anyone help me with this? I can not figure out what is going on..
thanks.

Forgot to add – when I enable the themes across the network and then activate twentyxs only in the subdomain it changes the theme in the main domain as well.

And I just noticed this had been mark resolved so I will start a new thread b/c it has not been…

Red Flags: “an index.php in the subdomain folder” “the twenty eleven that came with my orig install, the twenty twelve that came with the subdomain”

A multisite network is still just one instance of WP files. One “wp-config.php” in one directory. It sounds like you have a jumble with two(or more) instances of WP using the same database.

The “subdomains” of a multisite are virtual, you will not see “subdomain folders” via ftp.

Instructions to activate a multisite network when you have a single version up and running: https://codex.www.ads-software.com/Create_A_Network

“WordPress must be installed in the root of your webfolder (i.e. public_html) for subdomains to work correctly. They will not work from within a subdirectory.”