This activity grants permission on the list item or folder. You can override or append user grant permissions.
Value of permission field by default can be one of the following values:
Full Control Design Contribute Read
If any custom permission levels are defined, you can also specify those. For help on creating custom permission levels see http://technet2.microsoft.com/Office/en-us/library/c5dd8b7e-202d-4d33-8535- 5c03f88ea1ff1033.mspx?mfr=true

The activity supports multi permission assignment. Use ‘,’ or ‘;’ separator to grant several permission. Example: “Approve, Read, View Only”.
SharePoint Workflow Designer Phrase
Grant this level permission on list item url to this user. Override current permissions: Yes
Parameters
Parameter | Description |
this level | Permission level string. Multi permission assignments are supported. Use ‘,’ or ‘;’separator to grant several permission. Example: “Approve, Read, View Only”. |
list item url | Full list item or folder url Ex: http://mysharepoint/MyDocs/Shared%20Documents/MSOMS.pdf http://mysharepoint/Lists/List%20with%20Approve/1_.000 http://mysharepoint/Lists/List%20with%20Approve/DispForm.aspx?ID=1http://mysharepoint/Lists/List%20with%20Approve/EditForm.aspx?ID=1 http://mysharepoint/MyDocs/Shared%20Documents/Folder |
this user | User name. Ex: “user@domain”, “domain\user”. It allows multiple valuesseparated by a semicolon. |
Override current permissions | No – a new permission will be added to existed permissions Yes – a new permission will override (remove) all old permisions |