how I can install macOS11 on my iMac , for some reason is not showing that needs to update
help
iMac 27″ 5K, macOS 10.13
help
iMac 27″ 5K, macOS 10.13
Check compatibility with your Mac.
macOS Big Sur is compatible with these computers - Apple Support
Check compatibility with your Mac.
macOS Big Sur is compatible with these computers - Apple Support
FWIW, a 5K 27" iMac is compatible.
See this page on how to install: How to get old versions of macOS - Apple Support
how I can install macOS11 on my iMac , for some reason is not showing that needs to update