Verify the contact info and whether it was sent by email or SMS. Then check Forms Sent 
under the contact to confirm delivery. 

• Double check there aren’t any typos in the email address. 
• Have the user check their Junk Mail or Spam folder.
• Try sending by SMS instead of email.
• Try a different email account.
• Click on the View icon (Eyeball icon) beside the sent form and copy the form URL.  Paste this URL into any other communication channel you have with your client (What'sApp, Messages, other Email Addresses etc.)
• Please note that there have been issues reported with icloud.com email addresses.