If you using zsh then you need do the add the following to your .zshrc
Steps: Step 1: Open your .zshrc profile
open -e .zshrc
Step 2: Add the following to the file
export PATH=$PATH:/Users/${YourUser}/Library/Android/sdk/platform-tools
export ANDROID_HOME=/Users/${YourUser}/Library/Android/sdk
Step 3: Save the file and close. Step 4: Reload the .zshrc
source .zshrc
Step 5: Check the devices connected
adb devices