These are from the dictionary
help and support
give/lend/offer etc somebody a helping hand
She’s been giving me a helping hand with the children.
spoken to help someone do something
Can you give me a hand?
give (somebody) a hand with
Shall I give you a hand with that bag?
I guess "give someone a hand" is more about helping with physical things such as moving a table or holding a bag for someone. And, "give someone a helping hand" is more about helping with non-physical things such as talking children to school or taking care of elderly people or supporting life of someone.
Are there any differences between "give someone a helping hand" and "give someone a hand"?