You can view digital collectibles in both MetaMask Extension and Mobile, as well as MetaMask Portfolio.
The easiest way to display your collectibles is to turn on the app's NFT autodetect feature. If you have automatic NFT detection enabled, MetaMask will automatically fetch any collectibles you have on Ethereum mainnet. Other networks are also supported, but you need to add them manually. Kindly refer to this FAQ for details on adding NFTs to your MetaMask wallet.
MetaMask now launches MetaMask Portfolio to help you manage your collectibles in a single place. Get a clear, comprehensive view of your accounts and assets across all networks by connecting your MetaMask wallet. All the collectibles from Phosphor should be displayed automatically.
If you still need help finding your collectible, please reach out for support.
The best way to claim the collectible on mobile is to use the MetaMask mobile in-app browser. Copy and paste the claim link that you received in your email and open it in the MetaMask in-app browser. You should be able to continue the claim process.
Simply tap on the MetaMask browser extension icon or make the switch in the MetaMask mobile app. Phosphor would automatically detect the change.
You will have to initiate a transfer through the blockchain. Sending a digital collectible through MetaMask is very similar to sending conventional tokens. Kindly refer to this official guide for sending and receiving NFTs through MetaMask.