Auto-Response Rule

Auto-Response Rule:

Steps:

In Classic:
1. Be ready with the email template.
2. Setup > Lead > Customize > Leads > Auto-Response Rules
3. Click on New Button 
4. Name the Auto-Response Rule, check the box below it and Save
5. Open the Auto-Response Rule you just created
6. Click New to create Rule Entries as per your requirement and save them
7. Make sure the Auto-Response Rule is Active
8. Test it

In Lightning Experience:
1. Be ready with the email template.
2. Click the setup icon > In Quick find box on the left > Search for Lead Auto-Response Rules (Feature Settings > Marketing > Lead Auto-Response Rules) 
3. Click on New Button 
4. Name the Auto-Response Rule, check the box below it and Save
5. Open the Auto-Response Rule you just created
6. Click New to create Rule Entries as per your requirement and save them
7. Make sure the Auto-Response Rule is Active
8. Test it