The Nuxeo defaultly provides Title and Description in its layout. I suggest you to load ur own layout in order to override the default layout given by nuxeo. So according to your need, create a “layout-contrib.xml” as below.

<extension target="org.nuxeo.ecm.platform.forms.layout.WebLayoutManager"
    point="layouts">
    <layout name="ur_layout_name">
        <templates>
            <template mode="any">/layouts/layout_default_template.xhtml
            </template>
        </templates>

        <rows>
            <row>
                <widget>Montant</widget>
            </row>
            <row>
                <widget>client</widget>
            </row>
            <!-- As many fields u want-->
        </rows>

        <widget name="Montant" type="int">
            <labels>
                <label mode="any">Montant</label>
            </labels>
            <translated>false</translated>
            <fields>
                <field>lds:intField</field>
            </fields>
        </widget>

        <widget name="client" type="text">
            <labels>
                <label mode="any">Client</label>
            </labels>
            <translated>false</translated>
            <fields>
                <field>lds:textField</field>
            </fields>
        </widget>
    </layout>
</extension>

We need to define our own schema which defines few datatypes. So declare ur schema in core-types-contrib.xml.

<schema name="layout_demo_schema" prefix="lds" src="schema/layout_demo_schema.xsd" />

Define the datatypes which are needed. For example, here we want int, text, date field etc. So create ur schema layout_demo_schema.xsd and define these datatypes.

<xs:element name="intField" type="xs:int" />
<xs:element name="textField" type="xs:string" />

Don't forget to declare your layout in ui-types-contrib.xml.

<layouts mode="any">
    <layout>ur_layout_name</layout>
</layouts>

Even I wanted a similar customized folder type metadata and have a look at the attached image how i achieved. That's all, its easy to create custom fields in nuxeo and to play with it.