Model is LG 27MS73V.Get the model number from the back and post it here.
The TV uses Miracast for screen sharing, so your source needs to support it. Windows PCs do, most Android devices also do, no idea about iPhone.
Casting is a different thing altogether.
USB recording is supported.
All these things are mentioned (with steps) in the user manual:
Yeah, I don't have problems finding all the options, my TV supports it but never really worked properly. Works initially and then cuts out, despite numerous firmware updates over the years, no joy. Android phone. My iPhone can't even see it but always picks up a Samsung Q7 we have in the house. TV's connected via Ethernet
USB recording; it has the options and I know what to press. Tried different hard drives and USB flash drives and have an army of them. TV always moaned that it can't find a compatible disk whereby another telly, a Samsung just works with whatever stick you plug in including cheapo unbranded ones. I blame their software and am hoping it's all improved since. But anyway, this is the one I'm looking to replace so doesn't matter now I guess!