The employee may thru appointment letter, employee rule book, standing orders.
The employee may also demand FNF statement in writing under acknowledgment and let the company reply in writing.
If obtaining NOC is a part of the policy of the company employee may obtain from HOD's and ask for NDC, work experience/service certificate and relieving letter. Relieving letter is issued post all settlements. If the employee has served notice period/paid notice pay, submitted company property, paid back advance/imprested cash/loan etc then nothing is pending/due at end of employee.
The purpose of preparing full and final statement is that as per company records the dues payable to the employee are............as mentioned in FNF statement and usually companies mention that employee may give acceptance on copy and if the acceptance is not received say in 1 month time the contents shall be deemed to be found true and payments shall be disbursed accordingly.
The issuance, acceptance, disbursement places on record nothing is due to be paid.
You have posted "(Settlement is already done)." This settlement must have been done on the basis some statement, excel sheet, work sheet.
If the employee is satisfied nothing is pending to be paid to him, then settlement is already done and nothing is pending.
Other alternative is employee may prepare a statement of payables by him to company and by company to him and sit with accounts/HR and confirm the entries or submit this statement to company and ask to confirm it as accurate. If company does not confirm and employee feels some dues are not passed by company employee can rake up the issue.