How to get recipient link to which email channel or email template via code?

I'm not sure I understand what you're trying to do from your screenshot and description.

Can you link to some documentation that describes the feature you're working with?

Yes, I follow this document to send email but don't where we can get ContactInfo data
https://github.dev/Kentico/community-portal/blob/main/src/Kentico.Community.Portal.Admin/Froala/CustomRichTextEditorConfiguration.cs
because you can check my question, Kentico require input recipient but we can not get it related to Email Channel or Email template

It's not clear to me how the CustomRichTextEditorConfiguration (which you linked to above) relates to ContactInfo data.

If you are trying to send an email to a recipient, you need to set up recipient lists and subscription forms for your visitors.

Review the email marketing guide in our docs for more information about this topic.

ah sorry, I give you wrong document.
should be like this https://github.com/Kentico/community-portal/blob/main/src/Kentico.Community.Portal.Web/Features/Support/SupportEmailSender.cs

It still is not clear to me what you are asking about.

The SupportEmailSender class that you linked to makes sure emails are sent to website visitors when they submit a form. That form is not created with the Form Builder, which is why I need to programmatically send the email in code.

If the form was created with the Form Builder I could use an automation or form autoresponder, and both are configured in Xperience's administration UI, not in code.

The email recipient data for the email sent in SupportEmailSender comes from the form data submitted by the visitor. There's nothing special going on here. The ContactInfo comes from ContactManagementContext.CurrentContact as you can see in the source code.