Searching the forum is a great way to discover and learn the answers to your Access programming questions.
These commands will allow you define what they can or can not do based on the True or False argument.
Me.AllowAdditions = True
Me.AllowDeletions = True
Me.AllowEdits = True
Check out the AllowAdditions Property in Access help for some more examples and options on how to control what your users can do. Use the forms OnOpen event when using these type of commands.
Search the forum for more examples on how to turn those properties on/off based on a users network name or workgroup name.