Hi, and welcome.
A reproducible example, called a reprex is always more helpful than a screenshot.
Here's why. There is no "mpg" package on CRAN, so I have to assume you were trying to bulk install packages by defining "mpg" as a collection of packages. However, if you did this with
mpg <- c("abc","def","hgi")
install.packages(mpg) # no quotes
it would work. In this case, only for abc, which is an actual package, but not for the others.
In RStudio, use the Tools | Install Packages dialog box, and separate multiple package names with a space or comma.