For etching, ou have to get the fibre remover gel (which is costly btw) and also velvet like cloth (which is also very costly) – silkscreen the gel onto the velvet with your desired design, let it dry and then iron it! wait till it goes completely brown, scrap of the dried bits and tadah you’re done!!!
Whereas for bleaching, you can do it at home with cheap materials – ie. unwanted tees and bleach. For experimental purposes, just fold your tee shirt in any way that you want to and spray on the bleach and let it dry in the sun and boommz!!