Hist table for character string in R

Question

I have a list of data (csv file). I've imported the data into my RStudio. When I try to make a histogram table in order to observe the frequency of each category I get this error:

'x' must be numeric

hist(tested_individuals$`Corona_result`, 
  breaks = 3, 
  main = "Corona test indication", 
  ylim = c(0,1100), 
  labels = c("0","1","2"))