Put your clothes flat in the middle. Make it smooth. No wrinkles.
Seal it all around.
In fact, signature T-shirts don't need to be framed deliberately.
Just fold it neatly and put it away.
Not easy to be framed. For example, it is too inconvenient to move or something.
And the cost is too high. Two pieces of glass, plus the labor cost of sealing, are not cheap.