you can use cdata symtax in xml file, for example:

<field name='text_field><![CDATA[
Within this Character Data block I can
use double dashes as much as I want (along with <, &, ', and ")
*and* %MyParamEntity; will be expanded to the text
"Has been expanded" ... however, I can't use
the CEND sequence. If I need to use CEND I must escape one of the
brackets or the greater-than sign using concatenated CDATA sections.
]]>

</field>

on website template you can use "t-raw" or "t-ecs" for render this value:

https://www.odoo.com/vi_VN/forum/help-1/question/what-is-the-difference-between-t-esc-and-t-raw-92184