How do I load two different companies on one quickbooks app on my phone to enable me to manage both companies through one app on one phone

Welcome to the Community space, theuns.

Accessing your companies simultaneously isn't possible in one mobile app. However, you can easily switch between different companies and access them one at a time.

For iOS devices:

1. From the main menu, select Settings. 
2. Choose Switch Company.
3. Select a different company.

For Android devices:

1. From the homepage, select the hamburger menu.
2. Select the All tab. You'll see the Switch company option toward the bottom.
3. Choose a different company.

Additionally, you can refer to this article with the guide on personalizing your invoices: Customise invoices on the QuickBooks Online mobile app.

Return to this thread if you have other concerns with your QuickBooks company. We'll be here to help you in any way we can. Have a great day.