peace Anjum,
There are those who believe in a freeform salat (what they call prayer), which means the format and content are not defined therefore you can select whatever to recite from Quran, add personal supplication and praise of God etc if you choose to.
In duaa (call/petition/supplication) one can say whatever is in one's heart to God, anytime, anywhere, short/long, lying down, standing etc etc, i.e. however/wherever/whenever you want.
The regular/timed salat is different however. You can read my view
here.