Can an admin user (master) do time tracking using the same login credentials in the mobile app?

Good to have you here, finance.

The login credentials for accessing QuickBooks Online (QBO) through your mobile app should be the same as the web version. However, the Time Tracking feature is unavailable in the QBO mobile app International version. The Admin or the user needs to log in through the web to track and bill customers for the number of hours consumed in a project or activity.

You can check out this article for more details about turning on and setting up time tracking in QBO: https://community.intuit.com/articles/1776887.

I have a link here that contains articles about managing money in and money out transactions: https://community.intuit.com/browse/quickbooks-online-intl-moneyin-moneyout.

Please reply to this post if you need anything else with time tracking in QBO. I'm here to help.