When you’re using the regular version of Safari that runs on your Mac or Windows PC, setting a site as your home page is as simple as going to the General tab in System Preferences and typing in a URL.
You can’t do that on the iPhone, but you can:
Add your `would be` home page to your bookmarks list, and then move it to the top of the list.
It does requires an extra tap: tap on the bookmarks icon, then on the bookmark itself