I am using email-to-case functionality to create cases from emails.Currently mail description are storing in standard case description field. My requirement is to store the email description as rich text in a custom field. I tried with process builder and workflow But i con't able to find solution.
Thank-you

I created a custom feed filter visualforce page with ref this link ( https://developer.salesforce.com/docs/atlas.en-us.case_feed_dev.meta/case_feed_dev/case_feed_dev_guide_general_customizations.htm )

In this feed view the inline images in email messages are not displaying it is displaying as link.

When I send mail from salesforce two email message records are creating, But I am sending one mail only not sure what is the problem please help.



Update:
It is happening only if i send mail to email-to-case mail id

I need the id of selected values from selectlist in my apex

page:

<apex:page controller="test">
        <apex:form>
            <apex:pageBlock>
                <apex:pageBlockSection>
                    <apex:OutputPanel >
                        <apex:selectList value="{!selectedwing}" size="5" multiselect="true" >
                            <apex:selectOptions value="{!ListOfwing}"/>
                        </apex:selectList>
                    </apex:OutputPanel>
                </apex:pageBlockSection>
            </apex:pageBlock>
        </apex:form> 
    </apex:page>

controller:

public with sharing class test {
    public list<String> selectedwing{set;get;}
    
    public List<SelectOption> getListOfwing(){
        List<Wing__c> wing = [select id,name from Wing__c] ;
        List<SelectOption> wingOptionList = new List<SelectOption>();
        for(Wing__c u : wing ){
            wingOptionList.add(new SelectOption(u.name , u.Name));
        }
        return wingOptionList;
    }
    public test(){
        
        
    }
}

 

When I send mail from salesforce two email message records are creating, But I am sending one mail only not sure what is the problem please help.



Update:
It is happening only if i send mail to email-to-case mail id

I am using email-to-case functionality to create cases from emails. I have used a custom field say mail_body__c(rich text area) to store email body and updating the field using trigger. this is working fine. Now my requirement is to store all incoming emails(from customers) related to a particular case in the custom field mail_body__c. How can I acheive that? Any help on this would be highly appreciated. Thanks.