Alem and a friend in the US have created a product they want to sell online. Leo says that shipping to other countries will involve tariffs and taxes. So it's important to fulfill in country. Leo says that Amazon does fullfillment and they specialize on small businesses and can handle overseas shipping as well. If it's a tech product, there's also NewEgg. Both handle fullfillment for small businesses.
This is one of those things that should be left up to someone else to do. Leo recommends looking into a couple of websites that will handle the ecommerce and site to sell the tshirts:
They do everything, including the site. They have a free trial, so he should try it first.
This also has a free trial, and will handle everything for him.
Leo recommends trying both before opening any store to see which one he likes best.