In Islamic terminology Dua is the act of supplication , Its calling out to Allah swt ,our creator who can hear us , Allah our creator , the All knowing and the All powerful 
its the way to ask Allah swt our needs 
prayer or Dua is obedience to Allah , he ordered us to ask him and he will answer 
the prophet peace be upon him said(A slave becomes nearest to his Lord when he is in prostration )
so we have to increase supplications in prostrations.
Dua is muslims way of feeling that connection to Allah at anytime , in any place to ask any thing for himself , his family , friends , strangers , anyone.
And make your dua to ask for good in this worldly life and in the hereafter
Quran full of Duas you can read it , or any needs from your heart