Prepping and casting a label tube in pen blank. Create your own pen label design. 

www.amazon.com/gp/aw/d/B07WPX9GYZ?ref=ppx_pt2_mob_b_prod_image

I have used several successfully, but the link I posted is my preference.

I use Microsoft word. There are measurements posted online for corresponding pen kits. Let me know and maybe we can set up a phone call and I could walk you through it.

I use Open Office, which is free, but just like Aidan says, select your image then "format" then "position and size". Put in your numbers and save. You can use a regular sheet of paper if you're doing multiple images in order to cram them all on one sheet and not overlap. That gives you a proof sheet to see your spacing. After a bit, it becomes second nature with moving images around the sheet. Then print your decal sheet. If you only print/cut out one image you can back the hole with paper so your printer accepts the "holey" sheet for another round of printing.