Thank you for clarifying, @Saeed. I suggest that you have a few tasks before you. First, if you have not already, look in to the security provided by Privilege sets, so that you have sets based on departments and positions within each. For example, in most of my solutions the Finance department has almost "read-only" privileges with the exemption of a few fields like financeNotes, auditBy, etc. HR can add staff, define roles, credentials, emergency contact info, etc. but only have access to HR related layouts and data. And Staff can see their own HR record only, and so on.
Once you have that part of your solution well defined, I would look into scripted imports for the data you describe (in an excel file). Insist that the Excel layout be absolutely consistent as a template.
I suggest creating a new table into which the excel data is imported so that the data can be confirmed and possibly edited. (This step is optional, but my typical preference.).
Finally, on the "utility import layout" for the new table mentioned above, allow the appropriate user to call a script (by button) to update the appropriate records. Since this is an update process, you'll want to include a match field in your Excel data, typically an ID such employeeID in this case.
To expand this example a bit: I have such a utility in an inventory management system (same type of requirement) where an excel template is used by staff to enter the appropriate data. This is first done outside of FM (in Excel) only because they are bringing together materials from across the inventory and manipulating the data a bit. THEN the user opens the import utility layout, clicks a button to import the new data into the Utility Intermediate table; they are asked to confirm deleting the previously imported records; then asked to select the Excel file to import.
Upon the import, various rows are deleted (due to the template having some Sum totals and such, and a title row) and delete any blank records/rows that were in the Excel file. There are some additional scripts on the layout to run, and some scripted validation, etc. Once they're happy with the import, a button allows them to process it into inventory, updating what's needed or creating new records, etc.
I know this is long-winded, but I'm hoping to help you envision a process so that the requirements seem more obvious and accessible. When this type of process is new to someone, I often suggest to simply do each step manually, drawing from the menus and writing each step down as you complete it. This then will translate into much of your script(s).