timeNow(){
echo "$(date +%r)"
}
PS1='[$(timeNow)] \u@\h:\w$ '
It will give you a prompt like this:
[05:34:37 PM] user@Host:/path$
Notes:
~/.bashrc or /etc/bashrc or ~/.bash_profile or ~./profile file (depending on the OS) and save it.source ~/.bashrc (distro specific) after saving the file.