Summary

U.S. Citizen stencil, if you want to spray-paint your own shirt.
If you want to stand out or send a message.... like any T-shirt.

A stencil, if you feel a call to paint this onto your shirt ... spray paint is fast, but fabric paint probably better result.
a stencil if this fits a collar of a T-shirt. scale to fit. I printed at a slight angle to make it work on my ender machine, because heating at the edge is uneven on my machine.

For a very thin stencil, reduce your Z height to something like .75mm, or even 0.4 mm (two layers) and it will be very thin and flexible.
you can also stop the print if you want a thin version, or if you like the voids in the incomplete first layer (like i did on the last shirt as a sample).

Yes, of course, there are iron-on letters at the craft shop and you can make an iron-on transfer, but this is a 3dPrinting site. :-) so here is a 3 d thing related...

Time: it took me about 35 minutes to print each large stencil, on a very thin flexible version.
The small stencil is about the size of an index card, but based on the first two, will be difficult to get good paint through that.

Tip on the painting: Don't rush with the paint, but don't stop and try to redo it. you'll see.

https://www.tinkercad.com/things/3AnsFxjkmtL-us-citizen-stencil-150mm
https://www.tinkercad.com/things/0wFwEtQixVd-curved-collar-us-citizen-stencil
https://www.tinkercad.com/things/iXk5Y1zv141-us-citizen-stencil-3x5in

version 2 of the rectangle stencil fixes the part of the e that needed connection.

The 3x5 stencil scales very well @ 175% to about the full size width of my Ender printer, and the letters are surprisingly readable.

Also included is a reversed image .jpg if you just want to print that out and use a razorblade on a manila folder.
Also can print reversed on a heat-transfer page from the craft store.

all these are handicrafts if you don't have time to get a professional done one from any of the dozens available on other sites done by professionals.

Let's keep handy.

Peace
D.