Ability to let users to upload an excel file, which would populate form fields.

You mean your user will upload an excel file and this will fill your form fields, correct? I don't think that we have that feature that allows users to upload an excel file and it will fill the data uploaded by the user.

However, you can fill the form with your uploaded excel file, please check this guide https://www.jotform.com/help/442-How-to-Use-the-Spreadsheet-to-Form-Widget and see if this is what you are looking for.

Let us know if you have any questions or if you need further assistance. 

How can my website users copy/paste from excel into my form fields asking for their business addresses in separate fields. 

You can use the SpreadSheet widget in this case. You can have your users manually copy and paste value from their excel into you form field.

Kindly test this sample form here https://form.jotform.com/61441655557965.

Let us know if you have any questions or if you need further assistance. 

Unfortunately, this still forces my users to copy one cell at a time. Can we set this up to allow for multiple cells to be copied/pasted

It's not possible in the widget. You've mentioned an address section, are they on separate cells? If yes, you may consider using the Spreadsheet to Form widget. You will setup this widget to have a unique ID to fill multiple fields at once. Please check the following guide for the steps:

https://www.jotform.com/help/442-How-to-Use-the-Spreadsheet-to-Form-Widget 

Hmm... unfortunately I do not want my users going through additional steps to format their information to fill out my form, but if it's truly the only way then i can set it up for them as an option. i am trying to allow this capability to ease some users experiences who like to use excel to store their company data, and just want to copy and paste that data in. Do any of you believe the ability to copy from multiple cells in excel and paste into multiple fields in a form will ever be an option? I can currently paste from excel to other Microsoft programs such as word or NAVision. 

I have forwarded a feature request to our back-end team in your behalf. Please note that there is no estimated time-frame for an implementation. If this gets implemented in the future, you will be updated via this thread.