I am trying to create an existing pdf form by uploading from my computer, but I am not seeing an option to do this.

When i click on upload a form, an option is give to upload the form from a website or clone a form.  When I click clone a form it does not provide any options.

You cannot create a web form from a PDF form, you can just upload it and use it as it is. I would recommend you to simple use our drag and drop form builder, or search in our templates gallery or our Themes Store, where you can find ready to use forms.