Talking to them is the best way. Look through the Player's Handbook with your Dungeon Master and learn about Feats. You might want to tell your DM that they don't have to keep track of your Feats either. It's up to the players to remember whether or not they have a Feat and how it works. Feats are an important part of Dungeons and Dragons 5e, but it's up to your Dungeon Master (DM) to decide if they're part of the game or not. This is especially true if you try to use the innate magic loophole I talked about earlier.