add gift card to apple wallet

No, it is not possible, you can add a credit, debit, or prepaid card to the Wallet app.

See the following Apple articles:

Set up Apple Pay

Set up Apple Pay - Apple Support

Countries and regions that support Apple Pay

Countries and regions that support Apple Pay - Apple Support (EG)

Set up Apple Pay in Wallet on iPhone

Set up Apple Pay in Wallet on iPhone – Apple Support (UK)

how do i add a gift card from tesco

How to use your tesco gift card , see -> https://www.tescogiftcards.com/help-and-faqs

You can use Apple Gift card to add to your Apple ID balance, and use as a payment method.

See -> Add money to your Apple ID balance

Add money to your Apple Account balance - Apple Support (IN)