Hi Meenakshi
it's great to know that you started learning in Azure, but unfortunately, the free trial cannot be extended normally, you can upgrade to a pay-as-you-go subscription more details about this are given below.
https://azure.microsoft.com/en-in/pricing/purchase-options/pay-as-you-go
else you can choose to create another free trial account if you wish.
if you find this answer helpful kindly accept thanks