We currently support SMS and Email channels for the user verification. On the user table click the blue button labelled "Send Bulk Verification" 
. This will then pop up a modal box which shows you the options available for verification methods.
From this modal box you will select the delivery method for the verification message either SMS or Email or both.
From the modal box you will also select which user types will receive the verification message.
Here is a brief description of each user type.
Send to all: All users in the user table will receive the verification message
Send to non-verified: All users who have not yet verified themselves will receive the verification message
Send to selected: User that have been selected before clicking the Send Bulk Verification button will receive the verification message