There is no genuine, safe way to get free Robux, and the only Roblox codes you should redeem for free Robux are those you personally bought from a store or were given (in physical form) from a trusted friend or family member. Just like how no stranger on the street will ever give you money for nothing, the same goes for strangers on Roblox, Discord, or any other in-game community.
The age-old saying of "If it's too good to be true, it probably is" is something every Roblox player needs to remember.