В качестве @camille можно использовать rename_all
library(tidyverse)
mpg %>%
rename("tr ans" = trans, "mo del" = model) %>%
rename_all(~str_replace_all(., "\\s+", ""))
или rename_at
с everything()
mpg %>%
rename("tr ans" = trans, "mo del" = model) %>%
rename_at(vars(everything()), ~str_replace_all(., "\\s+", ""))