What did Hannah make and bring to young Samuel each year?

Answer: A little robe

Each year she brought him a little robe (KJV: coat) when she came up with her husband to offer the annual sacrifice.

“Now Samuel was ministering before the LORD—a boy wearing a linen ephod. Each year his mother would make him a little robe and bring it to him when she went with her husband to offer the annual sacrifice.”— 1 Samuel 2:18-19 (BSB)