You can use dplyr, base r, or the fs package. I prefer the fs package, but any will work.
### Data
data <- tibble(
V1 = c("23k", "34k", "100G"),
V2 = c("./foo/bar/test.bam", "./hey/you/test2.bam", "./to/far/to/go/test3.bam")
)
### DPLYR
data %>%
mutate(`File Path` = basename(V2))
### Base R
data$`File Path` <- basename(data$V2)
### FS
library('fs')
data$`File Path` <- path_file(data$V2)
data$`File Directory` <- path_dir(data$V2)