foo.xml

<?xml version="1.0" encoding="utf-8"?>
<form>
	<fieldset addruleprefix="Joomla\Component\Foos\Administrator\Rule">
		<field
			name="id"
			type="number"
			label="JGLOBAL_FIELD_ID_LABEL"
			default="0"
			class="readonly"
			readonly="true"
		/>

		<field
			name="name"
			type="text"
			validate="Letter"
			label="COM_FOOS_FIELD_NAME_LABEL"
			size="40"
			required="true"
		 />

		<field
			name="alias"
			type="text"
			label="JFIELD_ALIAS_LABEL"
			size="45"
			hint="JFIELD_ALIAS_PLACEHOLDER"
		/>

		<field
			name="access"
			type="accesslevel"
			label="JFIELD_ACCESS_LABEL"
			size="1"
		/>
	</fieldset>
</form>