Here are the steps in verbatim:
It only takes a few easy steps. Just follow the instructions below on how to purge your company. Note: Be sure you want to delete everything before you start the process.
1. Sign in to QuickBooks Online as an admin.
2. Delete all the text after the last / and type in purgecompany.
3. Type Yes to confirm that you want to delete your company data.
4. Press Wipe data.