There is many types of file upload with like blob storage, app service ,storage account with PowerShell

Lets ,I give you the example of file upload with blob storage

Prerequisites:

To access Azure Storage, you’ll need an Azure subscription. If you don’t already have a subscription, create a free account before you begin.

and storage account and container should be exist on your azure account

Please follow below steps,

Block blobs consist of blocks of data assembled to make a blob. Most scenarios using Blob storage employ block blobs. Block blobs are ideal for storing text and binary data in the cloud, like files, images, and videos. This quickstart shows how to work with block blobs.

To upload a block blob to your new container in the Azure portal, follow these steps:

1. In the Azure portal, navigate to the container you created in the previous section.
2. Select the container to show a list of blobs it contains. This container is new, so it won’t yet contain any blobs.
3. Select the Upload button to open the upload blade and browse your local file system to find a file to upload as a block blob. You can optionally expand the Advanced section to configure other settings for the upload operation. You can, for example, upload a blob into a new or existing virtual folder or by supplying a value in the Upload to folder field.

4. Select the Upload button to upload the blob.

5. Upload as many blobs as you like in this way. You’ll see that the new blobs are now listed within the container.