import plotly.graph_objects as go
fig = go.Figure()
fig.add_trace(go.Scatter(x=[1, 2, 3, 4],
y=[0, 2, 3, 5],
fill='tozeroy')
) # fill down to xaxis
fig.update_layout(title='<b>Title</b>',
xaxis_title='<b>x</b>',
yaxis_title='<b>y</b>')
fig.show()