Talk is cheep , show you the code.
Install
Clone this repository into $ZSH_CUSTOM/plugins (by default ~/.oh-my-zsh/custom/plugins):
1 | git clone https://github.com/zsh-users/zsh-autosuggestions ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-autosuggestions |
Add the plugin to the list of plugins for Oh My Zsh to load (inside ~/.zshrc):
1 | plugins=(zsh-autosuggestions) |
Start a new terminal session or run source ~/.zshrc.
More: zsh-autosuggestions/INSTALL.md at master · zsh-users/zsh-autosuggestions
Change default color
This color can be changed by setting the ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE variable.
For Example:
You can edit your ~/.zshrc and change/add the variable ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE='fg=value' like ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE='fg=66'.
The number of colors is in any case limited to 256(i.e. the range 0 to 255).
You can view the detailed colors from here:

When the auto prompt appears, press → key or Ctrl(Control) + f to enter the auto prompt command into the current terminal.