“From here, I can see the total quantity of items that have been invoiced to a specific customer. However, this view shows all quantities for all time. How can I filter this data to see the quantities for a specific period? Also, how can I generate a report showing the quantities that have been sold?”
The screen you that you show is not a report but a Tab listing of Customers. Here you could use Advanced Queries (Left of Search box) to create a report of what you see. Alternatively click on the Reports tab and create any default report there that may suit your needs.
By the way clicking Edit columns button (below the table shown) will allow you to see more fields in the tab listing.
Yes, I understand that custom reports can be used, but my issue is how to display and customize them properly. 
For example, I need a report for a specific period, a specific customer, and the quantities supplied or sold.
I did not refer to custom reports but to Advanced Queries (https://www.manager.io/guides/advanced-queries) and the Reports tab (https://www.manager.io/guides/reports).
Note from FAQ - Manager Forum that [emphasis added]:
- Be specific. Do not just tell us a feature does not work. Explain what you have done and why you think there is an issue. If your question relates to an apparent software problem (rather than an accounting topic), tell us your operating system (including the version), Manager edition (desktop, server, or cloud), and exactly what you think is wrong. If possible, post screen shots illustrating the problem. If your question is related to custom themes or custom reports, always post the code or report definition you have developed and the results it produces. Do not simply post a picture of something you want and ask other users to tell you how to achieve it.
Thank you for your response! I am trying to filter data in custom reports to display quantities for a specific customer within a specific period, but I haven’t been successful so far.
I also tried using Advanced Query, but it doesn’t fully meet my needs since it doesn’t show quantities for a selected customer over a specific time range.
