How to get selected value from another webpart?

I want to send a value from one form to another.

In this case i want to send "Watch" to the Title field at the bottom form.

I give the Title field JavaScript ID (ItemJS), then tried to add script:

var ItemName = document.getElementById("SPFieldText").innerText; NWF$("#"+ ItemJS).val(ItemName);

but it give error:

Uncaught TypeError: Cannot read properties of null (reading 'innerText') 

here is a reference for "SPFieldText"

Need help for my issue...