I recently received a screenshot of a USPS tracking number. It was well over 20 digits and I found it extremely burdensome, on my phone, to go back-and-forth to copy the numbers from the screenshot to the usps.com website. So, I tried something different and it worked...
I said to my HomePod, "Hey, Siri, remind me to 638373947374..." and then a reminder appeared on my To Do list of only the digits which I could easily copy and paste into the post office tracking website.
I'm sure this will work equally well with other smart speakers.