Okay it makes a difference if your talking a hard drive or a memory card.
If it is the latter then there is usually a little plastic tab like part you moved accidentally and you can just push it back to make it writeable. Further it is normal for memory cards to use exFAT to be readable by many devices that can't read/write in NTFS format (digital cameras, cell phones, etc.)
If it is a hard drive, we can't validate WHO you are or your 'story' here and if a drive is write protected we will not provide steps to 'crack' the security on the drive, this violates the TOS of Toms Hardware. If you have a problem with a device you did purchase, contact the manufacturer for support / bring it back to the store so they can validate who you are / you own the said 'hardware'.