Using BOFC application user/admin can easily Clone Multiple Custom Field which is not possible in Salesforce standard process. As it would be tedious job to copy each field one by one.
Follow the below mentioned link for to Clone Multiple Custom Fields in Salesforce using BOFC - https://www.bofc.io/clone-operations/explore-the-steps-of-clone-multiple-custom-fields-from-one-object-to-another-object-in-salesforce-in-few-clicks/