Hello,
To change home page setting go to setting>>reading and select home page from here:
Refer:
https://prnt.sc/srgybv
For header footer, I am telling you some thing, when you are creating header from elementor and want to use this template for a single page or full website you have to select page template elementor canvas in which by default theme header footer does not display that menas you have to create both template header and footer otherwise you have to use by default both,
Thanks,