I hope this makes sense.
Let's say we have a form on a screen where the user fills in the fields but if they don't fill in certain fields like "Alternate contact name", then PowerFx just omits that from the output. Here is sample code and screenshot of what I mean:

Concatenate("Daytime Contact's Name: ", inpPrimaryName_1,"
Daytime Contact's Telephone #: ", inpPhone_1,"
Daytime Contact's eMail: ", inpPrimaryEmail_1,"
Daytime Contact's Working Hours: ", inpWorkHours_1,"
Alternate Daytime Contact's Name: ", inpAltContactName_1,"
Alternate Daytime Contact's Telephone #: ", inpAltContactNum_1, "
Alternate Daytime Contact's eMail: ", inpAltEmail_1, "
Alternate Daytime Contact's Working Hours: ", inpAltHours_1,"
"
)