How do get my iPad to sync again with my Fitbit?

You need to download the FitBit app to the iPad and sync the FitBit as per its own instructions with the App like you wold normally.

See here: https://help.fitbit.com/articles/en_US/Help_article/1873?c=Topics%3ASyncing&l=en_US&fs=Search&pn=1

and here: ‎Fitbit: Health & Fitness on the App Store

The App is designed for iPhone, but it works on iPad just fine.

Hello,

You will need to reach out to Fitbit’s support for assistance with their product.