Hazrat Shaikh Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) once mentioned the following:
Muraaqabah-e-Du‘aaiyyah refers to where one, while remaining silent, closes his eyes, and turns his attention to his heart and begins making du‘aa with his heart i.e. one does not make a verbal du‘aa with one’s tongue. While making du‘aa with one’s heart, one may make du‘aa for his Deen, his dunya, and for whatever needs one has.
However, one should also remember to include the Ummah of Rasulullah (sallallahu ‘alaihi wasallam) in one’s du‘aa by asking Allah Ta‘ala to bring favourable and good conditions upon the Ummah and grant them success.
On account of the Ummah being linked to Rasulullah (sallallahu ‘alaihi wasallam), when one includes the Ummah in one’s du‘aa, then this will be a means for one’s du‘aas gaining acceptance by Allah Ta‘ala.
Note: Just as it is permissible to make du‘aa verbally, it is also permissible to make du‘aa in one’s heart, as mentioned above by Hazrat Shaikhul Hadith Moulana Muhammad Zakariyya (rahmatullahi ‘alaih). However, it should be borne in mind that on those occasions where it is established that Rasulullah (sallallahu ‘alaihi wasallam) made a verbal du‘aa (e.g. after salaah, after the azaan, after eating, etc.) then one should recite these masnoon du‘aas verbally in order to practise upon the sunnah. Nevertheless, at other times, one can make du‘aa to Allah Ta‘ala verbally or in one’s heart.
(Qutbul Aqtaab Hazrat Shaikhul Hadith Moulana Muhammad Zakariyya [rahmatullahi ‘alaih] pg. 434)
Source: Ihyaauddeen.co.za