Most printable rakhi products we found were cards. A rakhi is a bracelet — the thread a sister ties on her brother's wrist for Raksha Bandhan — and a version a child makes from paper and thread gets tied on an actual wrist, not opened like a card.
The core custom is simple and well documented: a sister ties a rakhi — a decorated thread or bracelet — on her brother's wrist for Raksha Bandhan. A child-made paper-and-thread version follows that same use: made beforehand, tied for real on the day.
A folded paper shape threaded onto cord or ribbon, decorated with whatever the child likes, ties on exactly the same way a bought one does. It does not need beads or elaborate finishing to work — it needs to survive being tied and worn.
Any accompanying words, gifts, or specific customs around Raksha Bandhan vary by family and region. We are describing the object a child can make, not prescribing how your family marks the day around it.
Threading a simple folded shape works from about four or five with help finishing the tie.
Families vary in who ties a rakhi on whom, and that is a family tradition to follow, not something we are going to define.
Some families extend the custom more broadly. Follow whatever your own family does.
Part of our guide to World calendars & interfaith families.