Here’s a more professional and clear rewording of your message:
Please note: You are required to check in and check out using the form below only when you are physically present at work. Do not complete this form remotely or for any reason other than actual attendance and task fulfillment.
Both check-in (morning) and check-out (evening) must be completed for your workday to be officially recorded. Any day without both entries will not be counted.
If there is any indication that the form was filled without being on-site or without actual work being done, that entry will be invalid and you will be held accountable for any incomplete or unfulfilled tasks.
DO NOT Misuse of this process,. Please take it seriously.