Welcome to Yamaha Synth.

For live performance can we select different voice direct by pressing onboard keys 1 to 16.

No. The "keys" always trigger playback of samples, and are used to perform music.

If you mean "buttons" [1]-[16], yes, this takes place in SONG MIXING and PATTERN MIXING modes, as these are the multi-timbral modes of the MOXF. As long as the

button is lit, numbered buttons [1]-[16] select the transmit channel assigned to that Track. Any PART or PARTs assigned to the channel will sound.

The SONG/PATTERN mode MIXING setups are not just for recording to the sequencer. They are for anytime access to multiple sounds is going to be required. Moving between 16 sounds in a seamless fashion is not only possible but enhanced in these modes.

Please see the following article on how to use this in your "live" setup:
Using a MIXING Program in your "live" Setup

My confusion is clear.
I seen all the videos on our site.In video voice selection by dial or inc dec button.

Suggestion: I think one training video should be given on site.

Thank you...Dear Friend

For fundamental navigation on your MOXF we highly recommend the CONTROLS AND FUNCTIONS section of the Owner's Manual. In particular, the explanation of what the buttons [1]-[16] do and when they do it found on page 15, you will find very useful.

Please see the article I linked you to for details on how to customize the MIXING setup to work for your needs.
If you have a specific question or you get stuck, post back here.