Hello caron208,
Thanks for reaching out to the Apple Support Communities! I see from your post that you're wanting to make some changes to the Background App Refresh setting on your iPhone.
You mentioned that you found it all greyed out when you went to Settings > General > Background App Refresh. When the feature is turned off, it will typically appear without the green "switches".
To make changes to the settings, you'll want to turn it on and then make the changes to the individual apps listed. You can learn more about it under, "Use Background App Refresh," from this article: Switch apps on your iPhone, iPad, or iPod touch.
If you're not seeing any way to turn it on at the top of the screen, be sure to Restart your iPhone, and try the steps again.
All the best!