You can view and download your invoices directly in your account.
To access your invoices, log in to your account and click on your name on the top right corner.
In the dropdown menu, select Plan & billing. This will take you to the page where you can check your billing history, the payment method that was used, and other information about your plan.
Click on Billing history and a new window will pop up allowing you to download your invoices in PDF format: