do i need norton

Nope! No antivirus is needed and should not be installed. You will find that there will be numerous problems after installing Norton or any other A/V. Feel free to do a search on these forums by clicking the "Search" option on the top of this screen.

No you don't need Norton, all it will do is slowing your devices down. macOS'ses and iOS'ses built in security are more then enough

I second Mac Jim D. Avoid all anti-virus software and that goes double for Norton.

See here for more detailed information about protecting your Mac:

Effective defenses against malware and ot… - Apple Community

And no, you absolutely don't need Norton or its ilk on your iPhone and iPad.