WiFi on boot without login

Mate 16.04 up to date on pi 3. Trying to configure wireless to connect without having to login to the machine.

I tried adding wpa_pk (encrypted) and WPA_ssid to the interfaces file with no success.

Is there a documented method that I’ve not been able to find?

I had a similar problem when I plugged my SD Card into a new Pi.

In the Networking setup tick “All users may connect to this network”.

Actually, the resolution involved completing the NetworkManager profile for the wireless connection.

Thank you, however.