Progress bars let users know that the system is working and needs a moment to catch up. This feedback reassures users and lets them know how much they might need to wait.
Use the progress bar when the system is loading an image, data, or module. The bar’s appearance changes to show the amount of time remaining.
Appearance and behavior
Here’s an example from QuickBooks Online Accountant.
The green bars show the user that the system is still updating the information or completing a task.