id <- "146Ng_b6wCcVNAVGwpej68yAkguZPHBak"
Data <- readr::read_csv(paste0("https://docs.google.com/uc?id=", id, "&export=download"),
col_names = TRUE
)
Data %>%
mutate( newdatetime = datetime+minutes(10))
creates a second column in blink of an eye.
Are you trying to create an extra ROW or extra COLUMN?
If you really wanted that as two rows this would then do that:
Data %>%
mutate( newdatetime = datetime+minutes(10)) %>%
pivot_longer(1:2)
But there are likely other columns you need to bring with it.