Unfortunately there isn't an archive tab! However there is always a way! Along the left hand side of your gmail you will see mail, chat, spaces and meet. Make sure you are on the mail tab and you will click "more". Once you click more you will see more options and you would then click on "All Mail". Once you are in all mail your archived message would be directed here. You can find the archive mail by knowing who sent it, the subject of the mail, the date it was sent or even context words in the email. Once you find the email you can determine if you want to delete it or move it back to your inbox if needed!