This is a beautiful dua we should recite often before Ramadan!
اَللّٰهُمَّ سَلِّمنِیْ لِرَمَضَانَ، وَسَلِّمْ رَمَضَانَ لِیْ، وَسَلِّمهُ لِیۡ مُتَقَبَّلاً ياَ أَرْحَمَ الرَّاحِمِينَ
Allahumma sallimni liramadana, Wasallim ramadana Li Wa Sallimhu li mutaqabbala.Ya Arhamarr Rahimin.
“Oh Allah! Safeguard me for Ramadan, safeguard Ramadan for me and accept it from me. O the most merciful of all those who show mercy!”