In the mobile application:  

For iOS devices: 

1. Open the Zoho One app on your mobile device, 
   
2.  Tap in the bottom right corner, then tap Applications.
3. Tap on the required app, then tap Assign Users under USERS.
   
4. Tap on the users you want to add, then tap Next.
   
5. Select the appropriate role for the user, then tap in the top-right corner.
   
6. Tap Done in the pop-up message that appears.

For Android devices: 

1. Open the Zoho One app on your mobile device.
   
2. Tap in the bottom-right corner, then tap Applications.
   
3. Tap on the required app, then tap under Users.
   
4. Tap on the user you want to add, then tap Next.
   
5. Select the appropriate role for the user, then tap .

In the web application:  

1. Sign in to Zoho One , then click Directory in the left menu.
   
2. Go to Applications, then click on the app you need to assign.
   
3. Click Assign Users, then go to the Individual tab.
   
4. Choose the users by manually entering their name and searching, or by using the user picker .
   
5. If required, set the application settings.
6. Click Assign.