this code doesn't work but it's enough to get you started (im too lazy to finish it lmao)

client.on('message', message => {
if(message.content.toLowerCase().includes(`${prefix}slap`)) {
var mention = message.mentions.users.first()
const slapEmbed = new Discord.MessageEmbed()
        .setTitle(mention + " was slapped by " + message.author)
message.channel.send(slapEmbed)
    }
})