Variable labels can be stored as the label attribute for each variable.
This functions sets all non-missing (non-NA) variable labels in a data.frame.
Usage
var_labels(x) <- valueExamples
x <- iris
var_labels(x)
#> Sepal.Length  Sepal.Width Petal.Length  Petal.Width      Species 
#>           NA           NA           NA           NA           NA 
var_labels(x) <- paste("label for", names(iris))
var_labels(x)
#>             Sepal.Length              Sepal.Width             Petal.Length 
#> "label for Sepal.Length"  "label for Sepal.Width" "label for Petal.Length" 
#>              Petal.Width                  Species 
#>  "label for Petal.Width"      "label for Species" 
if (interactive()) {
  View(x) # in RStudio data viewer labels are displayed
}