Different Dzogchen related traditions have different tak drols (liberation on wearing), which are generally mandalas with mantras included. They are very meticulously drwan by artists who know what they are doing, or now-a-days photocopied from well-done originals. Then they are consecrated by being coated with saffron water containing relics and sacred substances, folded a very specific way, and tied a very specific way. Then they are often put in a brocade, silk, (or similar) bag with a cord for wearing around the neck at the level of the heart. The Longchen Nyingthig (for example) has lots, you can see them on the Mahasiddha Nyingmapa website. Each has a specific purpose. We do these projects under the supervision of a master to make sure they are correct.
Mantras are handled differently. First copied, then consecrated similarly, then cut into long strips (without cutting any of the letters) and rolled around a short piece of incense in a specific direction and sealed with a little glue. One marks what is up and down with red on the top. You know have a tight neat little sealed scroll. These are used to full statues, stupas and permanent tormas. Right side up!
One time I made some of these rolls of various mantras (correctly), painted a tiny seed syllable of the deity's mantra, and sealed them in little test tube like glass containers that have a silver loop on top for suspending from a necklace or string. One of my lamas blessed them and we sold them as a little fundraiser for our group. He didn't object at all.