How to Make a WiFi Extender from an Ethernet Cable

Yes, when the extender supports access point mode. Connect the Ethernet uplink as described by its manual, then configure the WiFi network using the manufacturer's setup process.

They are different operating roles, although some devices support both. A range extender relays WiFi wirelessly; an access point typically broadcasts WiFi from a wired network connection.

Use the port and mode specified in the product manual. The same socket may be used for a wired client in extender mode and as an uplink in access point mode, depending on the device.

A wired access point can avoid relying on a wireless link between the main router and the remote device. Coverage still depends on the access point, placement, building and connected clients.