I am trying to find modifications in genomic location. Now, the output I am getting is in the chromosome and location of the modification (attached file). I am not sure how to convert it into a gene name using biomart or any other tool. Would you mind if you please helping me in fixing this issue? Here I don't have a range of base pairs. However, as shown below, I have just a position number in a particular chromosome number.

You could convert your information to GRanges, and then use annotatePeak from the ChIPseeker package. You can then filter the output based on which genomic region type your variants are in.