What do you mean screenshot who will be needed?
Which mobile OS are you using? Stating this information makes it a lot easier for people to assist.
If it's Android (although similar might be possible on iOS) have you tried going into your phones settings - scroll down to Google (Google services) and tap - is the correct Google account showing here? If not, tap on the email address and tap add another account. You should also be able to remove the incorrect account by tapping manage accounts on this device.
Apparently it uses whatever is currently selected in your "Google" app.
Go to "Google" app, tap top-right corner (account icon), choose the active account. Done, your fitbit assistant uses the selected account.
Best AnswerI just solved it right before your comment.
Best AnswerOpen the fitbit app
Tap the top left corner
Tap Sense
Tap Voice Assistant
Tap Google
Tap deactivate
Now set Google Assistant up. And log into the correct email address.