If you have an employee who is perhaps out in the field or in the office not able to add notes to a contact's record, then this tutorial will show you how to check Employee Permissions in order to see if this feature is disabled for them.
First, go to the Admin Page in MarketSharp.
Next look for the header of Employee Setup and click the link for Employee Maintenance.
Click the blue key next to Employee's name to access permissions 
Click the first list called "Feature Permissions" Then click the blue plus sign next to the Contacts Tab Permissions to expand it
You will have to adjust this permission for all 3 contact types (prospect, lead & customer)
If you notice in the above screenshot, the Edit and Delete options are unchecked for Notes, this is why the employee cannot add notes (just checking the edit will allow them to be able to add notes, I will leave it up to you if you want to give them the ability to delete notes). Do this for all applicable contacts and save the permissions, the employee will be able to add notes now.