You didn't specify model number, but there should be a button to lower and raise feed dog. You can purchase a darning foot if you don't have one. Make sure if you order one that you specify if you have a high shank, slant shank, or low shank so the darning foot fits your particular machine. I hope this is helpful.
Jimmy

Most Singer machine have a raised plkate these days, if you do not have one you will need a Singer store to get one.