my memory card is not working on my cell phone

[Joao]

I bought a SanDisk 256GB Extreme PRO® Card, put it in my cell phone which is a Poco M3 Pro and activated it to use it as internal storage for my files, it recognizes it as if it had it but in reality it still has 64 gigs

[karanamnagadurga.sai]

Hi @Joao

Have you checked our knowledge base articles?
(Get Support for Your SSDs and Flash Products | SanDisk)

Try this one.

• Quick Steps to Format External Drives on Windows and macOS

Have you opened a Support Case?
If not, contact SanDisk Technical Support for assistance.
(Contact Support | SanDisk)