[SalesForce] send an auto-response emails from the lead owner’s email when a new lead is created. How to do this

Set up default values for your fields. This is detailed in the documentation here and here.

Default field settings are available on one of the screens that appears when you are creating a field, to add them for existing fields use the Edit link next to the field name on the object's field settings screen.

Use default field values to make your users more productive by reducing the number of fields they need to fill in manually. Default field values automatically insert the value of a custom field when a new record is created. A default value can be based on a formula for some types of fields or exact values such as Checked or Unchecked for checkbox fields.

I tried the same thing in my sandbox. It works if I add the orgid to the query string. &oid=<your company org id> is what you need to add.

Before trying this in my org, I had to remove all the custom fields you had in your query string.

https://cs24.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8&first_name=Bob&last_name=Flynn&company=PMG&phone=5615889339&email=no%40mail.com&street=1234+Main+St&city=Delray&state=FL&Zip=33446&annualrevenue=100000&debug=1&oid=<CompanyOrgId>&online=true

I also had to change the case on some of the fields. Please notice the updated URL.