video conferencing to iphone; requires an email? Just have phone number

[1Billy]

I am hosting a meeting and am all set up to do that. The one person I am going to be video conferencing with is on a mobile phone. I want to send her an invite. I just have her phone number. Can I send an invite to her phone number to do a video conferencing?  In other words, do I have to have her email to send the invite? Thanks!