You can use the following functions to check which package version is loaded in R:

#display package version
packageVersion("ggplot2")

#display the date when this package version was released
packageDate("ggplot2")

#display description of the package
packageDescription("ggplot2")

The following example shows how to use these functions in practice.

Example: Check which Package Version is Loaded in R

Suppose we load the ggplot2 package in our current R environment:

library(ggplot2)

We can use the packageVersion() function to check which version of ggplot2 is loaded:

#display package version
packageVersion("ggplot2")

[1] '3.3.2'

We can see that version 3.2.2 is loaded.

To find out when this version was released, we can use the packageDate() function:

#display the date when this package version was released
packageDate("ggplot2")

[1] "2020-06-17"

We can see that this version was released on June 17, 2020.

And to view a description of the package, we can use the packageDescription() function:

#display description of the package
packageDescription("ggplot2")

Package: ggplot2
Version: 3.3.2
Title: Create Elegant Data Visualisations Using the Grammar of Graphics
Description: A system for 'declaratively' creating graphics, based on
        "The Grammar of Graphics". You provide the data, tell 'ggplot2'
        how to map variables to aesthetics, what graphical primitives
        to use, and it takes care of the details.
Authors@R: c( person(Hadley", "Wickham", , "[email protected]",
        "aut", comment = c(ORCID = "0000-0003-4757-117X")),
        person("Winston", "Chang", , role = "aut", comment = c(ORCID =
        "0000-0002-1576-2126")), person("Lionel", Henry", , role =
        "aut"), person("Thomas Lin", "Pedersen", ,
        "[email protected]", role = c("aut", "cre"), comment
        = c(ORCID = "0000-0002-5147-4711")), person("Kohske",
        "Takahashi", role = "aut"), person("Claus", "Wilke", role =
        "aut", comment = c(ORCID = "0000-0002-7470-9261")),
        person("Kara", "Woo", role = "aut", comment = c(ORCID =
        "0000-0002-5125-4188")), person(Hiroaki", "Yutani", role =
        "aut", comment = c(ORCID = "0000-0002-3385-7233")),
        person("Dewey", "Dunnington", role = "aut", comment = c(ORCID =
        "0000-0002-9415-4582")), person("RStudio", role = c("cph",
        "fnd")) )
Depends: R (>= 3.2)
Imports: digest, glue, grDevices, grid, gtable (>= 0.1.1), isoband,
        MASS, mgcv, rlang (>= 0.3.0), scales (>= 0.5.0), stats, tibble,
        withr (>= 2.0.0)
Suggests: covr, dplyr, ggplot2movies, hexbin, Hmisc, knitr, lattice,
        mapproj, maps, maptools, multcomp, munsell, nlme, profvis,
        quantreg, RColorBrewer, rgeos, rmarkdown, rpart, sf (>= 0.7-3),
        svglite (>= 1.2.0.9001), testthat (>= 2.1.0), vdiffr (>= 0.3.0)
Enhances: sp
License: GPL-2 | file LICENSE
URL: http://ggplot2.tidyverse.org, https://github.com/tidyverse/ggplot2
BugReports: https://github.com/tidyverse/ggplot2/issues
LazyData: true
Collate: 'ggproto.r' 'ggplot-global.R' 'aaa-.r'
        'aes-colour-fill-alpha.r' .....
VignetteBuilder: knitr
RoxygenNote: 7.1.0.9000
Encoding: UTF-8
NeedsCompilation: no
Packaged: 2020-06-17 06:03:58 UTC; thomas
Author: Hadley Wickham [aut] (<https://orcid.org/0000-0003-4757-117X>),
        Winston Chang [aut] (<https://orcid.org/0000-0002-1576-2126>),
        Lionel Henry [aut], Thomas Lin Pedersen [aut, cre]
        (<https://orcid.org/0000-0002-5147-4711>), Kohske Takahashi
        [aut], Claus Wilke [aut]
        (<https://orcid.org/0000-0002-7470-9261>), Kara Woo [aut]
        (<https://orcid.org/0000-0002-5125-4188>), Hiroaki Yutani [aut]
        (<https://orcid.org/0000-0002-3385-7233>), Dewey Dunnington
        [aut] (<https://orcid.org/0000-0002-9415-4582>), RStudio [cph,
        fnd]
Maintainer: Thomas Lin Pedersen <[email protected]>
Repository: CRAN
Date/Publication: 2020-06-19 13:00:03 UTC
Built: R 4.0.3; ; 2020-11-20 18:07:33 UTC; unix

-- File: /usr/lib/R/site-library/ggplot2/Meta/package.rds 

The description includes a brief explanation of what the package does, the authors of the package, where to report bugs, the publication date, and much more.