Among the small instruments people use for transferring beads or powder from their weighing dish to a capsule are a small spoon, a gem scoop, or a lab scoop. Others prefer a micro-spatula made of stainless steel, since these make it relatively easy to transfer tiny amounts in a controlled way.
Some people prefer to fill their empty capsules using a mini-funnel that’s small enough to fit inside the rim of their capsule. This requires knowing the diameter of the empty capsules that will be used. Most people choose one of the larger-sized capsules and then purchase a mini-funnel that fits. It’s also possible to make a functional mini-funnel at home with a partially rolled-up sheet of paper and tape.