What is Xenica and It's features?

Please check, http://servarica.com/xen/

Can I get a free trial before I start using your Xen Module?

Yes you can, just put the following promotion code in the order page - SWXSMFT

Is it compatible with XenServer 7,6 and WHMCS 5.x?

Yes, it is compatible with all of them.

Do you Support Windows VMs ?

yes :)

When clients chose password for a new product , the password changes after creating the VM!

Yes, its very important for your clients Security. every time a vm recreated it will get a new random password