A line chart (aka line plot, line graph) uses points connected by line segments to demonstrate changes in value. The horizontal axis depicts a continuous progression, while the vertical axis reports values for a metric of interest across that progression.
What is a line chart?
A line chart is essentially a connection between different data points. A line chart is determined by two axes: the xaxis often represents periods of time, and the yaxis displays a quantitative value.
EazyChart is a free online chart maker that offers the widest variety of line chart types (bar chart, column chart, radial chart, stacked bar, clustered bar, and progress bar). Here are their differences:

Line chart: Used to display events that occur over a regular time interval or period, such as the number of monthly visitors.

Area chart: A type of line chart where the area below the line is filled with a specific color. Example: Annual sales.

Multiaxis chart: A line chart that displays two variables with different units of measure organized within two yaxes. Example: temperature and precipitation.
When to use a line chart?
A line chart is typically used to show trends over time, showing relationships between two variables. You'll use a line chart when you want to highlight changes in values of one variable (plot on the vertical axis) for continuous values of a second variable (plot on the horizontal). This emphasis on shifting patterns is sold by line segments constantly moving from left to right and observing the slopes of the lines moving up or down.
A classic line chart can show the number of visitors to a website or the value of a company's stock over time.
Best practices for creating a line chart
Start the yaxis at zero. Otherwise, you risk a misinterpretation.
 Clearly label your axis labels so the viewer knows what they are comparing.
 Remove distracting graphic elements like gridlines, varying colors, and cluttered legends that can prevent the viewer from seeing the overall trend quickly.
 Avoid comparing more than 5 curves. Your graph should not become cluttered and difficult to read.
 The intervals must be of equal size.
 Lines should only connect adjacent interval values. If any data is missing, indicate so.