Once logged into Amazon Ads, you are at the campaign manager. You can see all your ad campaigns in the main part of the screen.
On the left of the page you will see a gear icon, click it, it is called Administration.
Then click Billing.
You will see a list of current charges so far this month.
Below that you will see Statements. Click the arrow if it is not pointing down already.
Click the current Year.
Click the latest month (or whatever month you want).
You will see a listing of the charges, you can then click download.
The last month can be delayed in the statments section. But there is a better way to see billing amounts in my opinion, as I like the breakdowns for each country in one PDF.
You can scroll lower and see Invoices. Click arrow if not pointing down.
Click the Paid link.
There you can see the billing date, the country, the amount,
You can then download it and see a breakdown of each ad more clearly here and the totals.
Keep in mind some amounts will be in countries currency that is different then yours and keep in mind your bank will convert these amounts to your home currency if they are not in your currency. As well, taxes may be charged on top of ad charges as well and service fees could be as well.
The charges will be for the previous month, 1st to last day of the month.

Keep in mind I have whited out the invoice number and amounts from this screenshot.
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