Yes, you can send a fax from a wireless printer if the printer has fax capability and the fax is physically connected to a landline phone line.
The “wireless” part of a wireless printer is only the connection between the computer and the fax machine. A wireless printer cannot send faxes wirelessly (without a landline phone line).
How to send a fax from a wireless printer with fax capability
Each model is different, so consult the manual for your individual printer/fax.
Most wireless printers with fax capability fax with the print driver. To send a fax, go to the document you want to fax and select “print…”.
Once the print dialog is open, the printer driver will have some options including the ability to “print” to fax.
The driver should have places to input the fax number, etc.
Once the fax is sent, the fax machine will attempt to dial the requested fax number.