My apps not working, I am unable to add services and products to my invoices.

Hello there, @barrygolds. Making sure you'll be able to add products and services to the invoices using the mobile app will save a lot of time. No worries when having trouble doing the tasks I'm here to help. 

Whenever you encounter issues while navigating using the QuickBooks Online (QBO) mobile app the initial step to fix it is by clearing the program cache. Doing this will eliminate the damaged files and will refresh the background process of the system. Follow along below to get this done right away. 

For Android:

1. Open the QBO app and select the menu icon.
2. Next, choose Settings. 
3. Then, click Refresh Data and select Yes.

For iOS:

1. Access the QBO app and click the menu icon.
2. Then, select Help & Feedback. 
3. Next, choose Refresh Data and click Refresh.

Once done, close and re-open the app to add products and services to the invoices again.

You can also reset the app's data by going to the Settings of your mobile device. I'll guide you on how:

For Android

1. Open your phone's settings and select Apps (varies by device). 
2. Next, choose the QuickBooks app and select Storage. 
3. Then, click Clear data.  iOS - From your phone's settings, select Settings, then, click on General and choose iPhone Storage. Select an app that's taking up a lot of space. To free up the storage without deleting the documents and data for the app, select Offload App.

For iOS 

1. From your phone's settings click select Settings.
2. Next, select General and choose iPhone Storage. 
3. Then, click the QBO app. To free up the storage without deleting the documents and data for the app, select Offload App.

On the other hand, you'll want to open your QBO account on a web browser and create an invoice from there. 

Let me know how this goes and feel free to leave a reply below. I'm always happy to lend a hand in case you have additional questions about creating invoices in QBO. Have a great day ahead and take care.