The statement if (message.content === '!help' || '!command') { has two blocks: message.content === '!help' and '!command'. The || or operator says: "either of those things should be true".
So it ignores the first block because the second block will always be truthy.
What you're trying to do is this:
client.on('message', (message) => { let targetMember = message.member.user; if (message.content === '!help' || message.content === '!command') { message.channel.send( `Hello ${targetMember}! This bot is currently used for testing only. Features will be added in the future, however for more info, please contact <@248030367666274304>.` ); }});