What to do with USB flash drive or SD card

MicroSD card: I got a 64GB microsd card. Printed on the card are: class 10, microsdxc 1, Lexar633x, 64GB. I understand this comes with exFAT. Now I need to change to FAT32 so that I can use it in a mp3 player. Home screen > Left top > Disk > Gear icon > format > fat32. It is not recognized by the mp3 player.

Format/Partion difference: I put the card back in computer. Gear Icon > Partition format. What is the difference between partition and format?

Thank you.