unable to change email

It is not clear how you are sending the invitation. In most cases Zoom offers an invitation copy to paste into an email. If this is the case then the default address is controlled by your email software and you may need to manually change the from before sending. If some other method is being used perhaps the following may help https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0063688