In a Stud.IO project I made I'm missing a specific printed part that isn't available in Stud.IO. So I used the Part Designer to create a custom part, which is basically just a normal 1x1 tile with the print as a decal. I got this properly imported into Stud.IO and by giving the part the correct BrickLink number in the Part Designer, I also got it to automatically link to the proper LEGO piece and the instructions show the proper part number, too.
This is all well and good, but now I want to share the Stud.IO file, with someone who doesn't necessarily have that part. Now the question is, will the custom part automatically be included in the Stud.IO model and work as expected or would the other person need to import that part on their system, too? If it doesn't work right away, what would happen instead? Would the part just be missing, as if the pieces are just not in the model or would anything else happen (like an error or some kind of dummy part being shown)?