last name

Hi all, I want to fill the DV-2026 form and have a question, I have married in July and haven't changed the last name yet. I intend changing it in the following months, but i'm worried that if i fill the form now with my maiden last name and then change all my documentation my enty can be...

So I have to two last names, my first last name that comes from my dad and my second last name that comes from my mom. Do I have to put in the entry form both last names in the field "Last/Family Name"? I have reasearched a bit and I haven't found a clear answer, some people say to put both of...