Great day to you, liverpoolbb,
QuickBooks integrate with hundreds of third-party software developers.
When it comes to integrating accounts, it would be best to contact the third-party application provider since the transactions that sync into your QuickBooks Online account depends on the transactions shared from the third party app.
They can guide and walk you through on how to handle linking account.
If there’s anything else you need help with concerning your QuickBooks Online account, feel free to reach back out. Have a great day!