Hi, and welcome!
Questions with a reproducible example, called a reprex will generally attract more and better answers, for future reference.
For an overview of the many packages in R for time series analysis, see the task view
Also, look at the example in help(ts)
## Multivariate
z <- ts(matrix(rnorm(300), 100, 3), start = c(1961, 1), frequency = 12)
class(z)
#> [1] "mts" "ts" "matrix"
head(z) # as "matrix"
#> Series 1 Series 2 Series 3
#> [1,] 0.07129375 -0.9559271 0.50141145
#> [2,] 1.04050834 1.2487662 0.15265760
#> [3,] -0.90468845 -0.8182468 0.23045436
#> [4,] -0.52113401 -0.1170084 -0.18582983
#> [5,] 0.50699136 -1.0571156 -0.03490444
#> [6,] 0.82524283 0.3112594 1.31767778
plot(z)
plot(z, plot.type = "single", lty = 1:3)
Created on 2019-12-17 by the reprex package (v0.3.0)