Example of a flexform with text, rich text editor (rte), file (image), date and multiple items (flexform sections)

date.xml

<dateName>
  <TCEforms>
		<label>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.dateName</label>
		<config>
			<type>input</type>
      <eval>date</eval>
		</config>
	</TCEforms>
</dateName>

file.xml

<fileName>
	<TCEforms>
		<label>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.fileName</label>
		<config>
			<type>group</type>
			<internal_type>file</internal_type>
			<allowed>gif,jpg,jpeg,tif,bmp,pcx,tga,png,pdf,ai</allowed>
			<max_size>5000</max_size>
			<uploadfolder>uploads/skinFlex/flex</uploadfolder>
			<maxitems>1</maxitems>
			<size>1</size>
			<selectedListStyle>width:200px</selectedListStyle>
			<show_thumbs>1</show_thumbs>
		</config>
	</TCEforms>
</fileName>

flexform.xml

<T3DataStructure>
  <meta>
   	<langDisable>1</langDisable>
	</meta>
	<sheets>
		<sDEF>
		<ROOT>
			<TCEforms>
				<sheetTitle>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.sheets.general</sheetTitle>
	        </TCEforms>
			<type>array</type>
			<el>
			<!--
        insert elements here
      -->
			</el>
		</ROOT>
		</sDEF>
	</sheets>
</T3DataStructure>

input.xml

<inputName>
	<TCEforms>
		<label>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.inputNmae</label>
		<config>
			<type>input</type>
		</config>
	</TCEforms>
</inputName>

rte.xml

<rteName>
	<TCEforms>
		<label>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.rteName</label>
		<config>
			<type>text</type>
			<cols>30</cols>
			<rows>5</rows>
		</config>
		<defaultExtras>richtext[*]:rte_transform[mode=ts_css]</defaultExtras>
	</TCEforms>
</rteName>
<!-- a typoscript configuration need to be added on thee field: parseFunc - https://gist.github.com/in8/5765989 -->

sections.xml

<items>
	<section>1</section>
	<type>array</type>
	<el>
		<item>
			<type>array</type>
			<tx_templavoila>
				<title>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.item</title>
			</tx_templavoila>
			<el>
        <!--
          insert elements here
        -->
      </el>
  	</item>
  </el>
</items>

textarea.xml

<textareaName>
	<TCEforms>
		<label>LLL:EXT:skinFlex/flex/locallang.xml:flexform.flex.textareaName</label>
		<config>
			<type>text</type>
		</config>
	</TCEforms>
</textareaName>

New variant for RTE:

<!-- Text -->
<settings.bodytext>
<TCEforms>
<label>Text</label>
<config>
<type>text</type>
<enableRichtext>1</enableRichtext>
</config>
</TCEforms>
</settings.bodytext>