name change, possible?

[fairy tale 0]

Hi, my wife (dual citizen, spanish and bolivia) wants to change her name when we start all the paperwork. Her current name is similar to this: First Middle Last1 Last2 so 4 names in total. Is it possible to change her first name to her middle name when we start filing all the required paperwork? She wants to use the following : "Middle Last1"  (middle in this case being the new first name). Or possibly use "Middle Mylastname" (We haven't decided if she wants to keep using her last name or if she wants to change it to mine).

 

Where do I even start with all of this? Is there something we have to do? She only has one american ID right now (military dependent ID, which is easily changeable). Also our marriage certificate (married in Texas) has her name as follows: First MiddleInitial Last1 Last2. Does that matter? Can we change her name on the certificate after getting married? But just in general, is what she wants possible to do? Or should we just avoid all this trouble and just use her name as it shows on the certificate/military ID? (First Middleinitial Last1) 

 

Thank you if this is confusing, but we want to make sure we do things the right way.