It's possible you are thinking of a different Pokémon game, or perhaps a fan-made creation. Could you please clarify what you mean by "member card"?
For example, are you thinking of:
* The Pokédex: This is a device that allows you to track and record the Pokémon you have caught. You can get it early on in the game.
* The Trainer Card: This is a card that shows information about your Trainer, like your name, badges, and Pokémon team. You can get it from your rival after you defeat him for the first time.
* A specific item that has a similar function in a different Pokémon game: If you can remember the name of the game or the specific item, I might be able to help!
Let me know if you have any other details, and I will do my best to answer your question!