Openfire cannot see Voip Option in Spark 2.6.3

Hello

I am very new in comunity so sorry if i have stupid question but one thing truble me mutch.

After instalation last version of OpenFire on my server Ubuntu 12.04 and configure basic things like domain etc, i also add 2 test users.

Then on two computers i install Spark 2.6.3 and configure connection on my new XMPP server. User are now connected and can do chat, send attachments BUT problem is:

I cannot see or i simply dont know how can user comunicate true VOICE.

1) Can anybody help me how to make VOICE call ?

2) Is possible to share screen true Spark connected on Openfire ?

Sorry for that but there is very little documentation for this on web. Or i am just soo stupid

Thanks for all your TIPs.

::