I got a new phone and couldn't remember my log in details so I created another account and would like to merge them together

Welcome to the Community, greatbuys8888-gm!

At the moment, we're unable to merge one QuickBooks Online subscription to another. You'll have to cancel one of the subscriptions to avoid getting double charges.

Furthermore, if you forgot your log-in details you can reset your User ID or password by clicking on the I Forgot my User ID or Password on the website. Here's how to reset your User ID and password:

1. Go to QuickBooks Online log in website.
2. Click on I forgot my User ID or Password.
3. Enter the information asked like email address or phone number and follow the on screen prompts.

If you've used your email to verify your account an email will be sent out to you to help reset your user ID or password.

If you wanted to cancel one of the QuickBooks Online subscription, you can check out this article for more detailed information on how to  Cancel your QuickBooks Online subscription.

Feel free to drop a comment below if you need more help with your subscription. I'll be here to help you. Have a nice day!