Your baby probably won't be able to feed himself with a fork and spoon until he's about 18 months old. But once he can sit in a highchair and feed himself at least part of his meal with his hands (which many children master by 12 months), let him experiment with a thick-handled, rubber-coated spoon.
Wait until after your baby's first birthday to let him try a fork. Before then, he could accidentally poke himself in the eye with it or hurt the inside of his mouth.
When you do offer your child a fork, choose one designed for toddlers, with short, dull tines.
AAP. 2013a. Developmental milestones: 12 months. American Academy of Pediatrics. http://www.healthychildren.org/English/ages-stages/baby/Pages/Developmental-Milestones-12-Months.aspx
AAP. 2013b. Feeding and nutrition: Your 2 year old. American Academy of Pediatrics. http://www.healthychildren.org/English/ages-stages/toddler/nutrition/Pages/Feeding-and-Nutrition-Your-Two-Year-Old.aspx