The tel: URI scheme works for making calls.
Use the open URL script step with a calculation of
"tel:" & table::phoneNumber
Thank you for your post.
@Mike Beargie (thank you for your response) is correct on both parts.
The "Dial Phone" script step seems to be the standard for this. You can also find details and examples here.
I hope this information is of use!
…and ask your customer to use the full phone number format including country code (e.g. 1-nnn-nnn-nnnn for North America). Otherwise it won't dial.
Better yet is to validate your user's input, so they can't save malformed phone numbers to your database.