Unable to read excel, showing "Is this a valid excel, there is no package called Pillar"

Unable to read excel, showing "Is this a valid excel, there is no package called Pillar"
But unable to install Pillar showing needs R Tolls

Please show the code you are running, including any uses of the library() function, and also the complete error message.

When I importing excel...Shwong "Is this valid Excel Fine ?, There is no package called Pillar". But When I am trying to install Pillar...
install.packages("pillar")
WARNING: Rtools is required to build R packages but is not currently installed. Please download and install the appropriate version of Rtools before proceeding:

https://cran.rstudio.com/bin/windows/Rtools/
Installing package into ‘C:/Users/162476/Documents/R/win-library/3.3’
(as ‘lib’ is unspecified)
also installing the dependencies ‘ellipsis’, ‘lifecycle’, ‘rlang’, ‘vctrs’

You may be running an old version of R. You can check your R version by looking at the first line of the output from

sessionInfo()

The latest version is 4.0.2. Try updating R and your packages.