How to I post to my wix webiste or to my facebook page so seniors can download the form themselves and submit it back to me?

If you are looking to use web forms, then you need to embed it: https://www.jotform.com/help/70-Adding-a-Form-to-Your-Wix-Site

Also, you can share the link of the form in a Facebook post or message: https://www.jotform.com/help/401-Where-to-Find-My-Form-URL

If you need to add it to your Facebook page, please check this guide: https://www.jotform.com/help/22-Adding-a-Contact-Form-to-Your-Facebook-Page

However, when you say "so seniors can download the form themselves and submit it back to me", does it mean that you want to use fillable PDF forms? If that is correct, please check this guide: https://www.jotform.com/help/212-How-to-Create-a-PDF-Form

Let us know if you need more help.