FAQ: How to preserve my formatting?
Coupler.io pulls data as it is stored in Google Sheets and does not copy formatting. At the same time, Coupler.io does not override formatting, set up in the destination file.
If you want formatting to be applied based on the imported data (e.g. highlight all rows with amount < $1000), please use conditional formatting: https://blog.coupler.io/conditional-formatting-google-sheets/
In other cases apply the needed format to the imported columns and next time your data is imported formatting will be the same.