If you don't have an iPhone you can't request a physical (titanium) card and you can't get the card number to use for online purchases. You can only use your Apple Card account to make purchases directly from Apple (and you use your Apple ID to do that). Also see the following from How to apply for Apple Card - Apple Support
If you apply online and don't add Apple Card to an eligible iPhone or iPad that you own, you can only use it to make eligible purchases online and in-store at Apple.2
footnote 2 - If you apply online, use a supported browser. To access and use all Apple Card features, you need to add Apple Card to an eligible iPhone or iPad that you own with the latest version of iOS or iPadOS. Then, you can manage your Apple Card on your device and make purchases anywhere Mastercard is accepted. If you don't add Apple Card to an iPhone or iPad that you own, you can only use your Apple Line of Credit for eligible purchases online and in-store at Apple.