As Linguist dnd 5e feat you have studied the languages and also the codes, you can also gain the below mentioned benefits.
- It can increase your Intelligence score by 1, to the maximum of 20.
- You can learn three languages according to your choice.
- You could ably create the written ciphers. Actually, the others can not decipher a code that you create unless until you would teach them and they do succeed on an intelligence check (DC equal to your Intelligence score + your proficiency bonus), or else they do use magic for decipher it.