apex:inputTextarea A text area input element. Use this component to get user input for a controller method that does not correspond to a field on a Salesforce object, for a value that requires a text area.
richText :- A Boolean value that specifies whether this text area should save as rich text or plain text. If set to true, the value saves as rich text. If not selected, this value defaults to false.
A text area input element. Use this component to get user input for a controller method that does not correspond to a field on a Salesforce object, for a value that requires a text area.
richText :- A Boolean value that specifies whether this text area should save as rich text or plain text. If set to true, the value saves as rich text. If not selected, this value defaults to false.
Please check below post for more info
https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_compref_inputTextarea.htm
Please let us know if this will help you
Thanks
Amit Chaudhary
to add placeholder to apex:inputTextArea use "html-placeholder" attribute.
For example,
<apex:inputTextArea html-placeholder="Type Message.." richtext="true"/>
This will work.