No, you cannot add or upgrade the internal storage of most modern MacBook Pro models after purchase, as it is soldered onto the motherboard. However, the MacBook Pro offers several storage configuration options at the time of purchase. For instance, the 2023 MacBook Pro starts with a base storage size of 512 GB and can be configured up to 8 TB. If you need more storage, you'll need to buy a model with a larger SSD configuration. Additionally, the MacBook Pro includes an SDXC card slot to use an external storage chip for additional space.