Can I designate required fields when creating my form?

In many use cases, I will need to have the ability to require that specific fields be filled out before the document can be saved, exported, or submitted. When making the decision of which form tool to use, this is going to be crucial.  

Is it possible to require fields?

Yes, it is possible to set the field "Required". Select the field and then click the "Required" button at the toolbar or right click on the field and then select "Required".

If the field is left blank, a pop up error will appear. 

You can change the form warning messages in the Preferences. Please refer to this guide: How-to-Change-Form-Warnings

Hope that helps. Thank you.