If connected my iPhone or iPad to a company wifi, can they accesses my data? Can they copy any images or read emails?
It is not possible for anyone to access your data after connecting your iPhone or iPad to a company Wi-Fi. Unless, the person hacks into your devices memory, they cannot access your data or files.
They might be able to see any web sites you Goto.
If they had a good reason too yes but they are probably not making the effort but they can see what web sites you go to or use.