Backup a single table
I'd recommend using the BCP utility.  From that documentation:

Copying table rows into a data file (with a trusted connection)

Basic

This example creates a data file named StockItemTransactions_character.bcp and copies the table data into it using character format.

At a command prompt, enter the following command:

bcp WideWorldImporters.Warehouse.StockItemTransactions out D:\BCP\StockItemTransactions_character.bcp -c -T