Default permission levels allow you to quickly and easily provide common levels of permissions for one user or groups of users.You can make changes to any of the default permissions levels, except Full Control and Limited Access.Edit: Add, edit, and delete lists; view, add, update, and delete list items and documents. By default, this permission level is assigned to the Members group. Contribute: View, add, update, and delete list items and documents.
From SharePoint 2013 and in Online, a new default permission level is given to the Members group i.e. Edit. In addition to the capabilities given by the Contribute permission level, Edit also gives users additional abilities to edit and delete existing lists, plus create new lists.Contribute Permissions - View, add, update and delete list items and documentsEdit Permissions - View, add, update and delete list items and documents + Add, Edit and delete Lists
Edit:edit +delete+add lists and librarys and list items,documentsContribute:add+edit+delete list items and documents only
Edit and Contribute are easily confused.Edit – Can add, edit and delete lists; can view, add, update and delete list items and documents.
Contribute – Can view, add, update, and delete list items and documents.