How to add money to Apple Cash wallet with Apple Gift Card?

How do I load Apple gift card to my phone

You cannot. Gift cards only add funds to your Apple account balance. The funds cannot be transferred. The article "What type of gift card do I have?" explains the different kinds of gift cards Apple uses, has links on how to redeem them, and what can be purchased with each kind. Click on the link --> What type of gift card do I have? - Apple Support

You cannot. Apple Gift Cards cannot be added to Apple Cash.

Please review the information in the Apple Support article I linked below.

How to redeem your Apple Gift Card or App Store & iTunes gift card - Apple Support