I have been using QuickBooks for a year now and entering mileage travelled every day but although showing on the app it's not showing on the computer version?

Let's do some steps to fix the non-syncing mileage logs on your app, melsweep.

You'll want to update the QBO app and sign out and sign back in to your QuickBooks company. This steps should refresh the connection and triggers to flow the mileage logs to be viewable on the QBO web interface. Please check out section Step 6 in the second article below about updating the app.

On the other hand, I'm not ignoring the fact that you've been using QBO for more than a year. Therefore, if this issue has been going on for a year now, please contact our QBO Support to investigate this behavior.

1. Click on Help and choose the Search tab.
2. Click Contact Us at the bottom.
3. Enter a sentence or two to describe the issue and click Continue.
4. Choose Chat with us.

I'm also sharing these articles for your additional reference:

• Automatically track mileage in QuickBooks Online
• Fix mileage tracking issues in the QuickBooks Online mobile app - Step 6: Update QBO app. 

Feel free to go back to this thread if you have other questions in mind.