One can easily add links to web pages in text fields and they even export correctly to pdf (which is great). However, many of the Figma files I make to export to PDF include phone and text numbers. I would like to make these clickable links much like they are on webpages.
Currently in Figma, When I enter “tel:” or “sms:” as the protocol, it shows the message “Invalid link”. A lot of these PDFs are sent via email and are opened on mobile phones/Macs so it is a common practice for me to make phone numbers clickable.
Right now I have to use Acrobat 
to linkify the phone numbers, and the way Figma currently exports PDFs is not very Acrobat edit friendly.
It would be a great addition to Figma to allow using protocols in URLs other than just “http:”/“https:”/“mailto:”. And, though I might not a use them atm, I can see others wanting to use custom, specific protocols for apps.