1. Open OpenIV
2. Go to GTA V/x64v.rpf/models/cdimages/streamedpeds_players.rpf/player_one
3. create backup of:

uppr_diff_004_b_uni.ytd

4. Extract files from this zip to a folder
5. Make sure to enable edit mode.
6. Replace the file with the Italia jerseys

uppr_diff_004_b_uni.ytd