Decide if the EEPROM Emulation is what you actually need, you can write to and directly manage FLASH. You could write data structures into FLASH.
Characters are just 8-bits of data just like any other. The EEPROM Emulation is likely to be exceedingly inefficient if you write a series of bytes to incrementing addresses.
STM32Cube_FW_F1_V1.7.0\Projects\STM32F103RB-Nucleo\Examples\FLASH\FLASH_EraseProgram
