Problem:

You are customizing SharePoint Form using the PowerApps.

As you may have noticed, PowerApps Drop-Down menu (Combo box) does not support SharePoint Choice fields property for Allow ‘Fill-in’ choices by the default.

Solution:

In PowerApps, create a logic that stores another text field value to Drop-down menu value. That way you can store the users fill-in choices to the SharePoint List in PowerApps forms.

In my example I have created SharePoint List which contains the following fields:

• Title
• My Drop-down menu (choice field)
  • values (choice 1, Choice 2, Other, please give your own value)
• HiddenTextField (Single line of text)

In PowerApps I have set If-statement to the HiddenTextField Visible-property.

If(DataCardValue2.Selected.Value ="Other, please give your own value", true, false)

So, when the user select value “Other, please give your own value” from the “My Drop-down menu”, HiddenTextField is shown in the form.

Then I have set If-statement to My Drop-down-menu (Combo box) Update-event.

If(DataCardValue2.Selected.Value="Other, please give your own value", {
'@odata.type': "#Microsoft.Azure.Connectors.SharePoint.SPListExpandedReference",
   Id: 0,
   Value: DataCardValue4.Text
  },DataCardValue2.Selected) 

So, when the item is saved in SharePoint list, PowerApps form takes the value from the HiddenTextField and saves it to the My Drop-down menu as “Fill-in choice”.

Conclusions

That’s it. You can store users Fill-in choices to SharePoint list also in PowerApps forms.