Tap: to touch something lightly with one's finger, often to get attention or to signal something.
Touch: to make contact with something or someone using one's finger, often in a gentle or exploratory manner.
Feel: to use one's finger to explore or examine something, often to determine its texture, shape, or size.
Poke: to touch something with one's finger in a more forceful or intrusive manner, often to test its texture or to get a reaction.
Nudge: to touch someone or something gently with one's finger, often to get their attention or to encourage them to do something