Make a target variable continuous time series Forecasting

Question

So I am performing EDA for time series data using Pandas. I have date time as an index and another column Units of Sale. My code is as follows:

def plot_df(df, x, y, title="", xlabel='Date', ylabel='Value', dpi=100):
    plt.figure(figsize=(16,5), dpi=dpi)
    plt.plot(x, y, color='tab:blue')
    plt.gca().set(title=title, xlabel=xlabel, ylabel=ylabel)
    plt.show()

plot_df(df, x=df.index, y=df.value, title='Title of Chart.') 

When I plot time against Unit of Sales I get a chart like this: I

However, I would like to get a more continuous chart that displays better. Something like this.

WHat transformation should I perform on the variable to make it continuous on the chart?