I have removed all the content of my Mac and I got to the last point - to Activate Mac
I have got to black screen that says Activate Mac. It asks to connect to Wi-Fi but I have no Wi-Fi icon in the top right corner. How can I connect to internet then? It is Macbook Air and there are no cable connection possible, I think.
Thanks
How exactly did you "remove all the content"? Here are the two options to do what you appear to be doing: How to reinstall macOS - Apple Support. and How to create a bootable installer for macOS - Apple Support
If you mean a "factory reset", that involves a bootable flash drive; the second option.
How you got to where you are now and what to do next is at least somewhat dependent on what you've done already.
I've never had an instance of no connection to internet possible as connecting is part and parcel of the procedure. The Mac is undoubtedly WiFi capable. But it does have ports and if you have no wireless, you'll have to use an ethernet adapter to connect to one of your Mac's port.
I have erased all content via system preferences.
Activate Mac
