Hi,
In general, if you don't have any resources in your subscription, there will be no ongoing charges. One exception to this is if you signed up for a paid support plan, which is a recurring charge each month.
In the Azure portal, navigate to your subscription. On left, click on Resources blade. Are there any resources in the list? If yes, one or more of these may have an associated charge.
On left, click on Cost Analysis blade. In here you can see actual and forecasted costs, cost by resource, cost by resource group, filter by specific date ranges, etc.
On left, click on Billing profile Invoices. In here you can view/download your Invoices. Another critical capability is to click on context menu (three dots) to the right of each invoice and choose Prepare Azure usage file. Once it is ready, you can download the usage file and view it in Excel/Sheets/etc. to see line-by-line individual charges that accrued during the invoice period.
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP