If my rank is 18,915 which college will I get!!?

Hey dear, make your question a bit more clear about what exam are you asking for. If you are asking about jee mains than this rank is very good for admission in some NIT'S and many other topnotch institutions. Also, it is a good rank for NEET exam. So, overall i would say you would get a good college with this rank. Use this link for college prediction for jee exam:
https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer
And below link for neet exam:
https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer

Hi you haven't mentioned about the exam or the course for which you want your rank to be considered. Clear your question so that it can be answered properly.