If you are giving the hub and bulbs, as a set, do not delete the bulbs from the hub. You may delete the hub from your account but this is not necessary.
Your friend or the next person who will be using the hub and bulbs will have to create a new Sengled Element account, reset the hub, and add them to their account.
If you are just giving Element bulbs to a friend, they will need to reset the bulbs and add them to a compatible hub.
For more information on how to reset a hub, please see the following article: https://support.sengled.com/hc/en-us/articles/228046967-How-do-I-reset-the-Element-hub-
For more information on how to reset a bulb, please see the following: https://support.sengled.com/hc/en-us/articles/219648347-How-do-I-reset-an-Element-bulb-