Hi Thesecretplayground, 

Great question! I totally understand how this might be confusing when initially setting things up -- you are certainly not the first/only Calendly user (or Calendly Community member!) to ask something along these lines. 

Let me break it down for you!

Please read below:  

• You can absolutely add a mandatory phone number question using Invitee Questions On Your Booking Page
  • the purpose of this field would simply be for you to gather that info (the invitee’s phone number), in case you need this info for data/phone call purposes etc. 
• When you implement an SMS Workflow, this results in an optional phone number field on the booking page - this field is added automatically/cannot be removed or edited, nor can it be made mandatory
  • SMS workflows cannot be mandated due to SMS laws/regulations that are above Calendly
  • while the text field will automatically appear when an SMS workflow is added to an event type, you cannot force invitees to input their phone numbers in this field - it will always be optional 
  • when an invitee chooses to input their phone number into this field, they can still opt out at any time after receiving their initial SMS message
  • when an invitee enters their phone number into a different phone number field, that is not associated with the SMS workflow/s 
• If you would like to guarantee that you receive the invitee’s phone number and use an SMS workflow, you will need to leave both fields on the booking page
  • this is because the invitee can choose to skip the SMS phone number field
  • if you need to have a phone number regardless, you cannot rely on the SMS field + should leave your mandatory question as well
  • many invitees will provide a different phone number for SMS messages than they do in the mandatory field - it’s not inherently redundant

You can read more about SMS Workflows here, as well as about more advanced Invitee Questions features here. 

I know this is probably not exactly what you’d hoped to learn, but do hope the info is helpful! Let us know if you have any more questions. It’s what we’re here for!

P.s. check out our New User Guide!