Naive, Mean, Holt, Damped trend, Exponential Smoothing and ETS Forecasting in R

Using In-built data in R
Downloading WDI data
Downloading Penn World Table Data
Downloading Covid Daily Data
Forecasting TS using Naive, Mean, Holt, Damped Trend, Exponential Smoothing and ETS (Error, Trend and Seasonality) Models in R