1. OpenIV
2. Go to GTA V/x64v.rpf/models/cdimages/streamedpeds_players.rpf/player_one/
3. Back up any files that you are replacing
4. Click edit mode click yes
5. Replace the file uppr_diff_004_a_uni.ytd
6. This texture will replace the "White OG T-shirt"

v2
Some Visual Edits