Most common technique (see Paukshte) – fold as you sew, stitch as close to the edge as possible, trim close to the stitching line, fold again, stitch again.
https://sewing.patternreview.com/SewingDiscussions/topic/78497
Rolled hem foot – a circle skirt or a scarf. Does not go over seams well.
Rolled hem on a serger – Katya – blouse – https://www.youtube.com/watch?v=9o66MVNfb3E
To prevent the hem falling off the fabric, increase the distance to the knife, use water soluble stabilizer or serge folded