Hazrat Shaikh Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) once mentioned the following:
Muraaqabah-e-Du’aa’iyyah refers to where one, while remaining silent, closes his eyes, and turns his attention to his heart and begins making dua with his heart i.e. one does not make a verbal dua with one’s tongue. While making dua with one’s heart, one may make dua 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 dua 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 dua, then this will be a means for one’s duas gaining acceptance by Allah Ta‘ala.
Note: Just as it is permissible to make dua verbally, it is also permissible to make dua in one’s heart, as mentioned above by Hazrat Sheikhul 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 dua (e.g. after salaah, after the azaan, after eating, etc.) then one should recite these masnoon duas verbally in order to practise upon the sunnah. Nevertheless, at other times, one can make dua to Allah Ta‘ala verbally or in one’s heart.
(Qutbul Aqtaab Hazrat Sheikhul Hadith Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) pg. 434)