It is very easy to setup the custom fields and email notifications, I assume you need assistance to setup them in your website.
I have done below modifications in your website:
q1) Edit the custom field group "Contacts":
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Setup the custom fields as you mentioned above:
~ a field for their email address (required)
~ an optional field for their phone number
q2) send me the content the visitor entered into the content field. I want to receive and be able to read each submission in my inbox.
Please try the first email notification "Website Inquiry" of your post form:
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Q3) I would like for the visitor's email address to be in the "From" field of the email. It would be nice if it printed in the message area of the email as well, but this is not required.
In above post form, section "Form editor", you can display both of custom fields:
- E-mail
- Phone
Q4) I would like that it not make a webpage for every submission.
In above post form, section "Settings", option "After visitors submit this form", choose option "Display a message instead of the form..."
Q5) I would like for the visitor's email address to be in the "From" field of the email. It would be nice if it printed in the message area of the email as well, but this is not required.
In the email notification "Website Inquiry" , you can display the custom email and phone field value with Types shortcode, like this:
Email address: [types field='email'][/types]
Phone number: [types field='phone'][/types]
Q6) send a friendly confirmation notice to the visitor who filled out the form.
Please try the second email notification "Thanks for contacting us" of your post form:
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Q7) after sending, it can redirect to a page that I will design. So a place-holder page for the time being will be fine.
I have setup a demo in your website:
1) Create a new page "Thanks for contacting us":
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2) Edit above post form, in section "Settings", option "After visitors submit this form", choose option "Go to a page"-> "Thanks for contacting us"
It is only a demo for your reference, you need to customize according to what you want.