Hello. My name is Michael. I can help you with your question.
When you move emails in gmail from the inbox to the archive, you are essentially just removing the inbox label (gmail calls what we typically call a folder, a lable - an email can have many labels associated with it - when all labels are removed, it is considered to be in the "archive").
All you should have to do is click on "all mail". The challenge is that you will have to wade through all the other email in there as well. When there is no label on the messages, they are just lumped in with all other messages.
You won't see them in your inbox or any other "folder" (since they don't have any label at all), but you will see them in "all mail". You can also search all mail in the search bar with all mail:searchterm.
Are you on the gmail website? (as opposed to in an email client)?
Also, are you absolutely certain that you didn't delete it? What I have described above is exactly how their archiving works. But I'm assuming you archived it in gmail from their web interface. If you used something else to archive it, that will be different.
I understand it's more than one. OK... Chrome is what I was assuming.
If you go into "all mail" that does indeed show all mail that is in your account. If you know what some part of one of the emails said, you can search there and that might give you an idea of where it is. Remember, since this is the all email folder, of you archived something from a few days ago, it will show MUCH further down on the list of email. Let's say I archived something on Monday, and since then I've received 100 emails and put them in their folders where I want them.... that archived item that might otherwise be by itself, will be the 101st item in the all email folder.
I have attached a screenshot of what the archived emails will look like. The archived emails are those that I have a red box around. You will see that the other ones have labels (folder names) on them. The absense of a label means it is archived.
Going forward - it would be best to create a place to put them rather than archive them. That way they won't be mixed in with ALL email. There is no way to view archived email by itself.
You can be guided through these steps to be certain about where the email is. If it isn't deleted, these steps will allow you to find it in the archive. It's basically what I have already told you, but it has examples and a little more detail.
All mail will include very piece of email in your gmail account. Even email in other folders. Do you know how to go to the next page in gmail?