I purchased a refurbished iPhone 8 Plus with no SIM card. How do I transfer the info from my iPhone 6s to the 8 plus using the 6s SIM card?

Welcome to the Apple Support Communities.

Remove or switch the SIM card in your iPhone - Apple Support, then Transfer data from your previous iOS or iPadOS device to your new iPhone, iPad, or iPod touch - Apple Support.

Jack

There is no information on the SIM card. You can simply move the SIM card from your iPhone 6s to the iPhone 8 Plus. This will not move the data from your old iPhone to your iPhone. You will have to perform the following to move data from your old iPhone to your new iPhone.

Transfer Data from old iPhone to new-

Do you have a backup created either on iCloud or on your computer?

Method 1 - Backup your old iPhone on your computer like this 👉 How to back up your iPhone, iPad, and iPod touch - Apple Support and then Restore your new iPhone from that backup like this 👉Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Method 2 - The Quick Start method and here is how to do that 👉  Use Quick Start to transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support

Axel F.