Can't install packages

install.packages("moments")
Installing package into ‘C:/Users/user/Documents/R/win-library/4.0’
(as ‘lib’ is unspecified)
Warning in install.packages :
'lib = "C:/Users/user/Documents/R/win-library/4.0"' is not writable
Error in install.packages : unable to install packages
Can you please give me a step by step solution?

Are you on a network dorive or somewhere that the C drive is not writable?