To record a bad debt write off, you'll first need to ensure that your account mapping is set up to the account you would like to record bad debt expenses in. Account Mapping settings are located in the Financial Settings under Accounts and can be accessed by users with the Books Admin permission.
Once your account mapping is confirmed, you can then write-off any outstanding receivable transaction in just a couple clicks.
Select the transaction you would like to write off.
Under the 3-dot / kebab menu in the top right, select Write off.
Verify the date and amount you would like to record for the bad debt write-off.
Click Save.