so i have this discord account that someone gave me and he also gave me a 16 digit code so when discord ask me the 2FA code i put my 16 digits number to that website and it generate my 6digit code to log in that discord account. i don't remember the place where i can generate my 2fa 6digits code with my 16 code . please help me

It's most likely standard secret key. Any 2fa app where you can manually add secret key (eg. Ente auth can do it) should do. Just enter name, secret key (your 16 digits) and save and that should give you usable codes