How can I see my mac address on Ubuntu?

Open a terminal and run ifconfig:

$ ifconfig | grep HWaddr

Use ip command instead of the outdated ifconfig

Command :

$ ip addr show

link/ether field of the output is the MAC address (Both for Wi-fi and ethernet connections, MAC address is represented by link/ether). Mostly this will be present in the second line.

Example :

$ ip addr show
1: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether a0:54:9f:53:b2:6e brd ff:ff:ff:ff:ff:ff

In my case a0:54:9f:53:b2:6e is the MAC address.

Try ifconfig, and look at the "HWaddr".