Block Blobs: It is an accumulation of small blocks that have their own unique block IDs. One block blob can contain up to 50,000 blocks. You can work parallelly by uploading multiple blocks at a time which decreases the upload time. The size of a single block blob is slightly higher than the normal, 4.75 TB, so the total size is 100 MB x 50,000 blocks. You can insert, delete, and replace blobs.
Page Blobs: They are comprised of 512-byte pages that are optimized for arbitrary read and write operations. To create a page blob, you must first define the maximum size of the blob. You can then add or update the content of the page blob. The maximum size of a page blob is 8 TB.
For details, click this link: https://intellipaat.com/tutorial/microsoft-azure-tutorial/azure-storage/