Ideally, you should ask your questions with a REPRoducible EXample (reprex), since you are new here I'm going to make one for you this time.
Consider that a histogram implies binding of values so you have to choose a binwidth suitable for your needs.
library(tidyverse)
library(lubridate)
sample_df <- data.frame(
Date = c("2010-09-21","2010-09-21","2010-09-21",
"2010-09-21","2010-09-21","2010-09-21","2010-09-21",
"2010-10-18","2011-07-08","2011-07-08","2011-07-09","2011-07-09",
"2011-08-06","2011-08-13","2011-08-16","2011-08-16",
"2011-08-31","2011-08-31","2011-09-13","2011-09-13","2011-09-13",
"2011-09-13","2012-09-10","2012-09-08","2012-10-01",
"2012-11-22","2013-02-19","2013-03-05","2013-08-03","2013-08-14",
"2014-08-20","2013-09-13","2015-03-16","2015-03-14",
"2015-08-13","2020-04-11","2020-04-18","2020-04-18","2020-04-22",
"2020-04-22","2020-04-23","2020-04-23","2020-04-23",
"2020-04-27","2020-04-27","2020-04-27","2020-04-29","2020-04-29",
"2020-05-11","2020-04-28","2020-04-28","2020-06-12",
"2020-06-12","2020-06-12","2020-06-12","2020-08-11","2020-08-15",
"2020-08-15","2020-08-15","2020-08-29","2020-08-29",
"2020-08-29","2020-08-29","2015-10-19","2017-09-10","2018-03-23",
"2018-06-24","2018-09-11","2018-11-11","2018-11-11",
"2019-02-06","2019-02-22","2019-03-12","2019-04-14","2019-07-31",
"2019-07-31","2019-07-31","2016-11-06","2017-07-13",
"2017-07-13","2017-07-13","2017-07-24","2017-07-24","2017-08-30",
"2017-08-30","2017-08-30","2017-08-30","2017-03-25")
)
sample_df %>%
mutate(Date = ymd(Date)) %>%
ggplot(aes(Date)) +
geom_histogram()
Created on 2020-09-04 by the reprex package (v0.3.0)