Line chart or line graph

              <record id="view_stock_level_forecast_graph" model="ir.ui.view">

<field name="name">Stock.forecast.graph</field>

<field name="model">report.stock.forecast</field>

<field name="arch" type="xml">

    <graph string="Stock Level forecast" type="line">

        <field name="product_id" type="col"/>

        <field name="cumulative_quantity" type="measure"/>

    </graph>

</field>

</record>

Bar chart

<record id="view_project_task_graph" model="ir.ui.view">

<field name="name">project.task.graph</field>

<field name="model">project.task</field>

<field name="arch" type="xml">

    <graph string="Project Tasks" type="bar" stacked="True">

        <field name="project_id" type="row"/>

        <field name="planned_hours" type="measure"/>

    </graph>

</field>

Pie chart

<record model="ir.ui.view" id="view_stock_quant_graph_value">

<field name="name">stock.quant.graph</field>

<field name="model">stock.quant</field>

<field eval="12" name="priority"/>

<field name="arch" type="xml">

    <graph string="Inventory Valuation" type="pie">

        <field name="product_id" type="row"/>

        <field name="qty" type="measure"/>

        <field name="inventory_value" type="measure"/>

    </graph>

</field>

</record>