Where can I buy the original T-shirt of apple?

The only place to get true, Apple apparel is at their store in Cupertino.

https://9to5mac.com/2016/10/21/apple-1-inifinite-loop-campus-store-merchandise/

Otherwise, it's either (I'm guessing) Apple approved clothing:

https://www.supergraphictees.com/product/apple-employee-style-logo-graphic-t-shirt/?gclid=EAIaIQobChMIpe2y4O7W9AIVS3xvBB2QfgEUEAQYASABEgJUlfD_BwE

https://www.supergraphictees.com/product/think-different-retro-apple-computer-logo-graphic-t-shirt/?gclid=EAIaIQobChMIpe2y4O7W9AIVS3xvBB2QfgEUEAQYAyABEgIyu_D_BwE

Or, stuff they sold in 1986, if you can find it.

https://www.mentalfloss.com/article/78553/1986-apple-launched-clothing-line

Other than in the flagship store in Cupertino, I don't think Apple sells shirts.