@MyAzQuery , Welcome to Microsoft Q&A Forum, Thank you for posting your query here
To track the Blob account Size for every month and Over all Size you can you Azure Monitor.
Calculate the capacity at the single storage account and different service level (Blob/Queue/Table/File) – via Portal.
- In the Azure portal, select Storage accounts.
- From the list, choose a storage account.
- In the Monitoring section, choose Insights
Additional information: This script calculates the size of a container in Azure Blob storage for the purpose of estimating billing costs.
Please let us know if you have any further queries. I’m happy to assist you further.
----------
Please do not forget to and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.