Setting up a military sharepoint, set up a form to allow soldiers to tell us if they have an issue (I.e. pay issue, legal, address change). But I need to hide this information from the other users because it could contain PII.
You can filter list view with Created Column By [Me]
In this way the user adding data would be able to see data added by him and will not be able to view data added by others
If you need advanced version for filtering by group you can follow this link
You can add SharePoint workflow on item addition that would impersonate the item and create Item level permission making your list item more secure.
You can use below reference: SharePoint workflow list item permission