Hi, We have mobile from requirement as below : Phone should get dial o

Are you using the Appian mobile App to open the link?
Note that the functionality is not uniform across all browsers/devices. For e.g. If you are using Skype, then its "callto" - so there isn't a standard as in "mailto".
Check if you can open the form using your mobile browser and if it'd let you invoke the dialer. It may be the restriction on the device side or API in understanding how to interpret the link.

Try tel: I have seen that tag being used on some sites.

Appian Does not allow other than http,https,mailto
There is an XML that to change your protocol edit or add
This was as of 6.6.7 though

Thanks for your inputs
@Sathya , we are using Appian mobile app to open link.
@rayudua, Could you please share more detail forXML change ? We are using Appian 6.7.1

the XML Rayudu is talking about applies to the browser. It wont have any effect on the mobile devices as Appian mobile App uses native mobile API's

Thanks Sathya
After all this discussion can we conclude that we can not give dial or texting feature for mobile form through Appian Mobile App ?

I think he is saying exactly the opposite. Have you tried the different tag?

Yes , We tried tel: and callto:

Hi Varsha,
I also have not been able to use the tel: and callto: tags in the link component to mark up a phone number. As far as I know, this feature is outside the functionality of the product.