Machines are tools that, in exchange for gems, give you cards so that you can complete your album. In addition, each of the cards contains a prize that will be awarded to you if you select that card on your board.
To access the machine room, you will need to press the "Get more cards" button located on the gift board in the "Gems" section of the game's Shop. Upon entering, you will see three classic machines, a temporary machine (it will depend on whether it is available at the time) and the VIP machine (it includes cards from temporary collections that you were unable to obtain at the time they were active).
We also recommend that you visit these articles: What are cards for? What is the VIP machine? What are the standard machines?